Pillar Guide · Updated May 2026

UK Emergency Tax Code: 1257L W1/M1/X, 0T and the Pension Lump Sum Trap in 2025/26

Each year around 8-10 million UK PAYE employees and pension drawdown savers are assigned an emergency tax code at some point — typically a 1257L W1/M1/X (non-cumulative basic) or, in more punishing cases, 0T (no Personal Allowance at all) or BR (flat 20%). Emergency codes are issued whenever HMRC and the employer cannot yet calculate the correct cumulative tax: new job without P45, post-redundancy pension lump sum, mid-year payroll switch, or annual code recalculation lag. For a routine PAYE employee the over-deduction is usually modest (£100-£500/year) and self-corrects via year-end P800. For a pension flexi-access drawdown the over- deduction can reach £10,000-£15,000 on a single lump sum, recoverable only by filing P53Z, P50Z or P55. This pillar guide explains every emergency code variant, what each does mechanically, the pension trap and how to claim back fast, the meaning of every tax code letter (L, M, N, T, K, BR, D0, NT) and how to read your payslip to spot the issue.

Last updated: 24 May 2026Last reviewed: 24 May 2026How we verify

What is an Emergency Code?

An emergency tax code is a temporary code that HMRC tells your employer (or pension provider) to use when the correct cumulative code is not yet known. Standard PAYE works cumulatively: each pay period the employer calculates total year-to-date pay and total year-to-date Personal Allowance, taxes the difference, and reconciles for everything paid earlier in the year. This self-corrects across pay packets, smooths uneven pay, and produces the right total tax by 5 April.

Emergency codes are non-cumulative. The W1, M1 or X suffix means “Week 1, Month 1, both” — each pay period is taxed in isolation as if it represented a full year, without looking back. The employer gives 1/52 (weekly paid) or 1/12 (monthly paid) of the Personal Allowance for each period, with no recovery of unused PA from earlier in the year. This is a stopgap that protects HMRC from under-collection while waiting for proper data.

The most common triggers: new job without a P45 (the leaving certificate from the previous employer that carries the year-to-date figures); pension flexi-access drawdown first withdrawal; mid-year switch to a new payroll provider; HMRC's annual code recalculation lagging the start of the new tax year; or material change in circumstances (marriage, second job, change of pension) before HMRC's records catch up. Emergency codes nearly always correct themselves within 1-3 pay periods once HMRC issues the right cumulative code.

1257L W1/M1/X — The Most Common

1257L is the standard tax code for 2025/26 — giving the full £12,570 Personal Allowance. Add W1, M1 or X and it becomes a 1257L emergency code: still giving the full PA, but on a non-cumulative period-by-period basis.

Mechanically, on a weekly payslip the employee gets £12,570 / 52 = £242 of PA each week. Pay above £242/week is taxed at 20% basic, with progression to 40% above £966/week (annualised £50,272 / 52) and 45% above £2,406/week. On a monthly payslip the PA is £12,570 / 12 = £1,048; basic rate ceiling at £4,189/month; higher rate ceiling at £10,428/month. The key restriction: if you started mid-year, the unused PA from earlier months stays unused on the emergency code. HMRC's year-end P800 will refund it after 5 April.

Worked example: an employee starts a new £40,000/year job on 1 October 2025. Under cumulative 1257L their PAYE would back-allow the 6 months of unused PA (April-Sept when not employed). They get a tax-free first month or so, then settle into normal cumulative deductions. Under emergency 1257L M1 they get only October's £1,048 of PA. Tax on October pay (£3,333) is £457 instead of (much lower) cumulative figure. Over 6 months Oct-Mar they pay roughly £400 more than they should — refunded via P800 the following autumn. Modest over-deduction, self-correcting.

0T — The Harshest Emergency Code

0T means zero Personal Allowance. Every pound of pay is taxed at the marginal band within the period — 20% up to £3,142/month (annualised £37,700), 40% up to £10,428/ month (annualised £125,140), 45% above. Like the W1/M1 codes, 0T is non-cumulative but unlike 1257L W1/M1 it skips the PA entirely.

0T is issued when HMRC has insufficient information to issue even a basic 1257L code. Common triggers: a brand new employee with no P45 and no Personal Tax Account history; an employee returning to work after a long absence from PAYE employment (1+ years); a pension flexi-access drawdown first withdrawal; or following a redundancy lump sum payment.

Worked example: a £45,000/year employee on emergency 0T M1 receives a £3,750 monthly gross. Tax: £3,142 at 20% = £628 + £608 at 40% = £243, total £871. Net pay £2,679 (plus NI deductions). Under correct cumulative 1257L the same monthly gross would carry tax of around £490 — annualised PAYE of £5,884 spread evenly. So 0T M1 over-deducts roughly £380/month while it remains in force. Get HMRC to issue the correct code as fast as possible.

BR — Often a Mis-applied Code

BR = Basic Rate, flat 20% on every pound. BR is technically correct for a second job or a pension paid in addition to a salary, but it is wrong if applied to your only employment. If you see BR on your payslip and this is your only job, HMRC has probably classified you as having a second job in error.

The over-deduction on a wrong-BR is substantial: the entire £12,570 PA is missed, so you pay an extra £2,514 (£12,570 × 20%) over a year. The error usually arises when HMRC's records show two open employments (the old job has not been closed properly in their records) and the new one is treated as the secondary.

Fix: log into the HMRC Personal Tax Account, navigate to PAYE income tax, and check the list of employments. If an old employment is still showing as live, mark it as ended (or contact HMRC by phone). New BR-coded job should switch to 1257L within 1-2 weeks once the old employment is closed. Over-paid tax to date is recovered cumulatively through the next pay packet — you should see a noticeable refund-shaped spike.

Pension Flexi-Access Drawdown Trap

Since pension freedoms in April 2015, savers aged 55+ can withdraw flexible amounts from defined contribution pensions, with 25% tax-free and the remainder taxed as income. The 75% taxable portion enters PAYE through the pension provider — but HMRC's default emergency code on a first withdrawal is 0T M1.

The problem: 0T M1 treats the lump sum as if it represented 1/12 of an annual income at that level. A retiree taking a £40,000 lump sum (£10,000 tax-free + £30,000 taxable) is taxed on the £30,000 as if it were £360,000 annualised — pushing into additional rate territory. The emergency tax extracted: roughly £30,000 × marginal calculation = £12,000-£15,000 instead of (say) £6,000 expected under proper code treatment.

The good news: the over-deduction is fully reclaimable. The route depends on circumstances:

P55: partial withdrawal, you continue making further withdrawals or working.
P53Z: full withdrawal of one pension pot but other pensions or income continue.
P50Z: full withdrawal of the only pension, no other income for at least 4 weeks.

Each form is downloadable from gov.uk, can be completed online via the Personal Tax Account, and HMRC typically refunds within 4-8 weeks. Without filing the form, you wait until the year-end P800 — typically 6-12 months after the withdrawal — for the same refund. Many pension providers now warn savers in advance and arrange to take a small “UFPLS test payment” first (£100-£500) that triggers HMRC to issue the correct code, so the main lump sum a month or two later is taxed properly.

P50, P50Z, P53Z, P55 — The Refund Forms

HMRC has a set of dedicated reclaim forms for emergency-tax over-deduction situations. Each is downloadable from gov.uk and submittable online via the Personal Tax Account:

Form	When to use	Typical processing time
P50	Stopped work and not returning for at least 4 weeks	4-8 weeks
P50Z	Full pension encashment, no remaining pension	4-8 weeks
P53Z	Full pension encashment but other pensions/income remain	4-8 weeks
P55	Partial pension withdrawal, continuing income	4-8 weeks
R40	Overpaid tax on savings, dividends or PPI compensation	6-12 weeks

Each form asks for personal details (name, NI number, address), the employment or pension reference, the gross payment and tax deducted, and the date of payment. You also estimate your expected total income for the tax year, which HMRC uses to calculate the correct tax liability.

Refund payment: by bank transfer if you have provided bank details in your Personal Tax Account, otherwise by cheque to your registered address. If you do nothing and wait for the year-end P800, the same refund arrives 6-12 months later via the same two routes — but interest on the overpayment is not added, so prompt reclaim is preferable. Refunds typically appear in your bank within 2 weeks of HMRC's processing confirmation.

Tax Code Letter Meanings

Each letter at the end of the numeric portion of a tax code carries specific meaning:

Letter	Meaning
L	Standard Personal Allowance (most common; 1257L = £12,570 PA)
M	Marriage Allowance recipient — PA increased by 10% (£1,260)
N	Marriage Allowance giver — PA reduced by 10%
T	Code requires HMRC review (e.g. income above £100k with PA tapering)
K	Negative PA — benefits/SP exceed PA, tax added rather than allowance subtracted
0T	No Personal Allowance — typical emergency, post-redundancy or first pension
BR	Basic rate flat 20% (second job; possibly wrongly applied)
D0	Higher rate flat 40% (second job, higher-rate combined)
D1	Additional rate flat 45% (second job, additional-rate combined)
NT	No tax (specific HMRC ruling, non-resident or foreign employer)
S prefix	Scottish taxpayer (S1257L = Scottish 1257L code)
C prefix	Welsh taxpayer (Cymru) (C1257L = Welsh 1257L code)
W1 / M1 / X suffix	Non-cumulative (Week 1 / Month 1 / both) — emergency basis

The K code deserves special note. It is used when HMRC's adjustments to your PA (e.g. state pension, large benefits in kind, prior-year tax owed) exceed the PA itself. Instead of reducing the allowance to zero (which would be 0T), HMRC adds the excess to your taxable pay. So K500 means £5,000 is added to your taxable pay each year. K codes are most common for retirees receiving a large state pension alongside private pension; the state pension is paid gross but must be taxed, and the K code does that by reducing what counts as PA for the private pension PAYE.

Reading Your Payslip

Every UK payslip is required by law to display the tax code currently in use. Find it near the top, typically labelled “Tax code” or “Tax Code”. If it ends in W1, M1 or X you are on an emergency code. If it shows 0T or BR for your only job, the code is probably wrong. If it shows 1257L without any suffix, you are on the standard cumulative code — usually correct.

Other useful payslip checks: gross pay (year-to-date), tax deducted (year-to-date), NI deducted, pension contributions, and net pay. If the cumulative year-to-date figures look out of step with what you would expect — for example, the YTD tax has suddenly jumped sharply or barely changed — the emergency code may have switched part-way and the cumulative reconciliation has triggered. Compare with your last payslip side by side.

Some employers (notably large enterprises and umbrella companies) provide additional detail on the payslip including the “tax basis” (cumulative or W1/M1), tax-free pay used to date, taxable pay used to date, and any K-code additions. Smaller payroll systems show only the bare minimum required by law. If you are unclear about anything on the payslip, your HR or payroll department can explain — or check the HMRC Personal Tax Account for the same information.

How to Fix an Emergency Code

Three paths:

HMRC Personal Tax Account: log in at gov.uk with your Government Gateway credentials, navigate to PAYE income tax, update your employments and any expected income. New code reaches your employer within 1-2 weeks.
Phone HMRC on 0300 200 3300: typically same-week update if you can reach an agent. Best call early morning.
Give your employer your P45: if you have a P45 from the previous job (issued automatically by the previous employer when you left), give it to your new employer's payroll. The P45 carries year-to-date pay and tax figures that allow cumulative coding to start immediately.

Once the cumulative code is applied your next pay packet may include a noticeable refund — the difference between what the emergency code over-deducted and what the cumulative code says should have been deducted. This is automatic and usually arrives without any further action from you.

If you are owed a refund that the cumulative catch-up does not cover (typically the case for pension flexi-access drawdown), file P50, P50Z, P53Z, P55 or R40 as appropriate. Once HMRC issues the year-end P800 you can also wait for that — typically October-November after the tax year end — but the wait can be 6-12 months and the cash flow impact can be material on larger overpayments. Prompt reclaim is almost always worth the 10 minutes to file the form.

Official References

FAQs

What is an emergency tax code?

An emergency tax code is one that HMRC issues to an employer temporarily when there is not enough information to calculate the correct cumulative tax. The most common emergency code is 1257L on a Week 1 / Month 1 / X basis — written as 1257L W1, 1257L M1 or 1257L X. The 1257L part gives the standard Personal Allowance of £12,570, but the W1/M1/X suffix means non-cumulative: each pay period is taxed in isolation as if it represented a full year, without looking back at year-to-date totals. Emergency codes usually correct themselves after one or two pay periods once HMRC receives the proper data.

When are emergency codes issued?

Several triggers. (1) New job without a P45 from the previous employer — HMRC has no recent data so applies an emergency code temporarily. (2) Starting a pension or annuity — same data gap. (3) Switching to a new payroll provider mid-year — the new system may apply emergency code while waiting for HMRC confirmation. (4) Material change in circumstances (marriage, second job, change of work) where HMRC has not yet recalculated the code. (5) HMRC's annual recalculation in April that does not complete in time for the first pay period. Emergency codes are designed to under-collect rather than over-collect tax in most circumstances, but they can produce both depending on individual situation.

How much extra tax does an emergency code take?

For a 1257L W1/M1 code: usually £100-£500 extra over a year for a typical mid-career employee. The non-cumulative basis means each pay period gets only 1/52 (weekly) or 1/12 (monthly) of the Personal Allowance, with no look-back. If you started a new job mid-year, the unused PA from earlier months is not refunded automatically through the code — it waits until year-end P800. For 0T (no PA at all), the over-deduction is larger — typically £1,500-£2,500 over a year. For a one-off pension lump sum withdrawal under flexi-access drawdown, the emergency-code overcharge can be £5,000-£15,000 on a single payment because HMRC's default treats the lump sum as if you would receive it 12 times a year.

What is the 0T tax code?

The 0T code gives zero Personal Allowance. Every pound of pay is taxed at the marginal band: 20% on the first £37,700 (annualised within the period), 40% on the next chunk to £125,140, 45% above. It is the most punishing emergency code because it skips the PA entirely. 0T is typically issued when HMRC has insufficient data to issue even a basic 1257L code — for example a brand new employee with no P45 and no Personal Tax Account history, or after a long absence from PAYE employment. It is also the standard code for pension flexi-access drawdown unless the saver has actively notified HMRC of expected total income for the year.

What is the BR tax code?

BR = Basic Rate. Every pound is taxed at a flat 20%, with no Personal Allowance applied. BR is technically not an emergency code — it is the correct code for a second job (where the first job already uses the full PA) or for a pension that pays in addition to a salary. But BR can also be wrongly applied as a quasi-emergency code on a new job if HMRC has not yet been told this is your only employment. If you have only one job and you see BR on your payslip, check with HMRC immediately — you are probably overpaying because your PA is not being applied.

How do I know if I am on an emergency code?

Check your payslip. The tax code is usually listed near the top, alongside your NI number and basic pay. Look for: (i) any code ending in W1, M1 or X (e.g. 1257L W1) — definitely emergency; (ii) the code 0T or 0T W1/M1/X — emergency or post-redundancy; (iii) the code BR if this is your only job — likely wrong; (iv) a code very different from 1257L without a clear reason (e.g. 500L, 800L) — could be a recent change. You can also check your HMRC Personal Tax Account on gov.uk — it shows your current tax code, the breakdown of how it was calculated, and lets you flag changes online.

What is the pension flexi-access drawdown emergency tax problem?

Since 2015 pension freedoms allow people aged 55+ to withdraw flexible amounts from defined contribution pensions, with 25% tax-free and the rest taxable. HMRC's default treatment of the first taxable withdrawal applies emergency code 0T M1 — which means the lump sum is treated as if it represented 1/12 of an annual income at that level. A £30,000 first withdrawal therefore looks like £360,000 annualised income to the payroll system, which applies marginal rates up to 45%. Result: roughly £10,000 of emergency tax deducted on a withdrawal that should have produced only £6,000 (assuming basic rate after the 25% tax-free chunk). The overpaid tax is reclaimable via form P55 (or P53Z/P50Z depending on circumstances) — typically refunded within 4-8 weeks. Many providers now warn savers of this in advance.

Which form do I use to reclaim emergency tax?

Depends on your situation. (i) Form P50: claim tax back after redundancy or unemployment, if you are not going to work for at least 4 weeks. (ii) Form P50Z: reclaim tax on a final pension lump sum (full encashment, no pension remaining). (iii) Form P53Z: reclaim tax on a pension lump sum where some pension remains but you have stopped withdrawing. (iv) Form P55: reclaim tax on a partial pension lump sum where you continue working or making withdrawals. (v) Form R40: reclaim overpaid tax on savings, dividends or PPI compensation. (vi) Self Assessment SA100: full annual reconciliation if you are already in SA. Each form is downloadable from gov.uk; HMRC typically refunds within 4-8 weeks.

What does each letter in my tax code mean?

The letter at the end of the numeric part of a tax code carries meaning. L = standard Personal Allowance (most common). M = Marriage Allowance recipient (you have received 10% of your spouse's PA, so your PA is increased). N = Marriage Allowance giver (you have given 10% of your PA away, so yours is reduced). T = code requires HMRC review (e.g. estimated income above £100,000 with PA tapering). K = negative PA — your benefits in kind, state pension, or under-payments exceed your PA, so tax is added rather than allowance subtracted (used mainly for retirees with large state pensions). NT = no tax (rare, used for some non-residents). BR = basic rate (second job). D0 = higher rate (second job, higher-rate combined). D1 = additional rate (second job, additional-rate combined). 0T = no allowance (emergency). Suffix W1/M1/X = non-cumulative.

How quickly does HMRC fix a wrong code?

Online via the Personal Tax Account on gov.uk: typically 1-2 weeks for the corrected code to reach your employer's payroll. Phone (0300 200 3300): often same week if you can get through the queue. By post: 3-6 weeks. Your next pay packet should reflect the corrected code; any over-paid tax to that point is usually refunded automatically through cumulative PAYE catch-up (the new code takes account of what you have already paid year-to-date). For one-off pension lump sums where the wrong code has already triggered a large over-deduction, the catch-up via PAYE may not be enough — file P50Z/P53Z/P55 to claim back faster (4-8 weeks for HMRC to process).

Related Calculators

Flexi-access withdrawal

Tax Refund

4-year claim window

Calculators for this topic

Income Tax Calculator

Work out how much income tax you owe using the latest 2025/26 UK tax bands.

National Insurance Calculator

Calculate your National Insurance contributions for 2025/26.

Student Loan Calculator

Calculate monthly student loan repayments for Plans 1, 2, 4 and 5.

Salary Sacrifice Calculator

Calculate how much tax and National Insurance you save by making salary sacrifice contributions to a pension, cycle to work scheme or EV car scheme.

About the author

Emma Clarke

UK Tax Writer

Emma Clarke has been writing about UK personal tax since 2018, with a particular focus on Self Assessment, PAYE coding and the practical mechanics of how HMRC actually applies the rules to ordinary salaries. Her work concentrates on translating the dense language of HMRC manuals and Finance Act schedules into worked examples that show, pound by pound, how income tax and National Insurance reduce a gross salary to the figure that lands in a UK bank account. Emma covers the full PAYE lifecycle: tax codes (1257L, BR, K codes, emergency codes), the Marriage Allowance, the High Income Child Benefit Charge, salary sacrifice arrangements and their effect on pensionable pay, the Apprenticeship Levy, and the differences between the rUK and Scottish income-tax regimes. She is particularly interested in the edge cases that catch PAYE employees out — the £100,000 personal-allowance taper, the 60% effective marginal rate it creates, and the interaction between student-loan plans and pension contributions. Every figure in Emma's articles is verified against the current HMRC rates pages and worked through a Self Assessment calculation by hand before publication. She writes to CalcHub's editorial standards: primary-source citations, plain English, no promotional language, and clear "this is general information, not financial advice" disclaimers where appropriate.

Personal-finance writer since 2018
UK tax specialism — PAYE, Self Assessment, National Insurance
Writes to CalcHub editorial standards (primary-source citation, annual review)

income-taxself-assessmentpayenational-insurancetax-codessalary-sacrificestudent-loansscottish-income-tax

Disclaimer: Tax codes, emergency code rules, refund forms and pension flexi-access mechanics change with legislation and HMRC operational practice. Figures here reflect 2025/26. Always refer to gov.uk and seek professional advice for large pension withdrawals or complex situations.