NI Number — National Insurance Number in the UK: how to apply, timelines, tax codes, P45 and tax refund
NI Number is a lifelong identifier in the format AB 12 34 56 C. You need it to pay the correct tax. Without it, your employer uses an emergency tax code (BR/0T) that takes 20% from all your income without the £12,570 tax-free allowance. A seasonal worker on BR for 26 weeks loses £1,257. Apply online on gov.uk — it is free and takes 10 minutes. You will receive a letter with your number in 4 weeks (SLA). During peak season (April–August) it can take 8–14 weeks. Help: 0800 141 2079 (England/Scotland/Wales, Mon–Fri 8:00–17:00).
What is an NI Number and why do you need it
National Insurance Number (NINO) is a unique lifelong identifier in the format AB 12 34 56 C: 2 letters + 6 digits + 1 letter. You get it once and it never changes (not when you marry, not when you change your passport, not when you go home and come back after 10 years).
Why you need it:
- Correct tax — without an NI Number, HMRC does not know your £12,570 tax-free allowance. Your employer uses an emergency code (1257L W1/M1, BR or 0T) — usually 20% is taken from all your income.
- National Insurance contributions — mandatory payments (8% on earnings above £242/week in 2026/27) for State Pension and social insurance.
- P85 tax refund — without an NI on your P45, digital submission is not possible. The paper route takes 8–12 weeks or more.
- Universal Credit, Child Benefit, Housing Benefit — if you need them.
- Student Loan, Personal Tax Account, credit score — all systems use the NI as a key.
An NI Number is NOT permission to work. Your right to work is checked through a Share Code (Home Office). Your employer must accept you and apply a temporary tax code while you wait for your NI. Refusing to hire you because you do not have an NI is illegal.
How to apply for an NI Number — step by step
- Go to gov.uk → "Apply for a National Insurance number" → you will be redirected to apply-national-insurance-number.service.gov.uk. It is free. Any payment = scam.
- Prepare your documents:
- Biometric passport (for NFC scanning)
- Proof of immigration status (visa stamp / eVisa share code / ARC)
- UK postal address (camp address on a farm is valid)
- UK mobile number + email
- Fill in the form — your name exactly as in the MRZ of your passport, date of birth, nationality, status. Reason for application: "working or looking for work" (for seasonal workers).
- Identity verification:
- Through the HMRC App or your smartphone browser — take a photo of your passport + a selfie with the passport next to your face. Requirements: no reflections, clear text, neutral background.
- If your passport does not have an NFC chip or the photos are not good enough, the system will send you instructions (certified copies by post or an in-person interview at a Jobcentre Plus). This adds 3–4 weeks to the waiting time.
- Save your Application Reference Number — it will be sent by email. Write it down! This is your ID when you call DWP if 4 weeks pass without a letter.
- Wait for the letter — it arrives by regular post to your UK address. Only UK — it is not forwarded abroad.
- Give your NI Number to your employer — the HR/payroll department will change your tax code to 1257L. Any overpaid tax will be returned in your next salary.
Phone help:
- England / Scotland / Wales: 0800 141 2079 (Mon–Fri, 8:00–17:00). Free from a UK mobile.
- Northern Ireland: 0800 587 0024 (Mon–Fri, 9:00–16:00).
- HMRC general tax help (with a free interpreter): 0300 200 3300.
- Asylum seekers with Permission to Work — separate helpline: 0300 200 3500.
The call centre does not have a fast track. Operators can tell you the status but cannot speed things up.
Tax codes — detailed explanation1257L vs BR vs 0T vs W1/M1 vs K — what each means, calculated on £500/week
A tax code is an instruction from HMRC to your employer. It tells the employer how much of your salary is free from tax. The basic allowance (Personal Allowance) for 2026/27 is £12,570, frozen until April 2031.
We calculate on a typical seasonal wage of £500/week gross and a 26-week season:
1257L (Cumulative — correct code)
- £12,570 / 52 = £241.73/week tax-free
- Tax: (£500 − £241.73) × 20% = £51.65/week
- NIC: (£500 − £242) × 8% = £20.64/week
- Net: £427.71/week
- Cumulative means that Payroll tracks your total income since 6 April and smooths out any ups and downs.
1257L W1 / M1 / X (Emergency — non-cumulative)
- Suffix: W1 (weekly), M1 (monthly), X (non-standard period).
- Used by default when you start your first job and HMRC has not yet verified your data.
- The numerical effect is the same as 1257L cumulative — BUT if you miss a week (sickness, unpaid leave), the allowance "burns" — it does not carry over to the next period.
- With a steady salary the result is the same as 1257L cumulative. With a variable salary you may overpay tax (it will be returned later through a retroactive adjustment).
BR (Basic Rate — no allowance)
- Used when: you have no NI Number, no P45, no Starter Checklist, or this is your second job.
- Tax: £500 × 20% = £100/week
- NIC: same £20.64
- Net: £379.36/week
- Compared to 1257L: −£48.35/week. For a 26-week season = −£1,257.10.
0T (Zero Tax-Free)
- Personal allowance = 0, but unlike BR it allows the higher rate (40%) and additional rate (45%) when you reach the threshold.
- For typical seasonal income (<£37,700) the effect is the same as BR: 20% on all income.
- The letter T signals that the code needs manual review by an HMRC inspector.
K-codes (Negative Allowance)
- Inverse: instead of a tax-free amount, a virtual income is added to your gross before tax is calculated.
- Used for corporate benefits (free housing, car) or old debts to HMRC.
- For seasonal workers — an anomaly. If you get a K-code, call 0300 200 3300.
Main takeaway: the difference between the correct 1257L and the wrong BR/0T on a typical salary is about £48/week. For a 26-week season = £1,257. This is lost income that you will have to get back through P85 after you leave (6–12 weeks waiting) or through a retroactive adjustment (1–2 pay cycles).
5 application scenarios — for different visasSeasonal Worker / Student / Skilled Worker / Family / ARC
1. Seasonal agricultural worker
You arrived yesterday and start work in 1–3 days. A camp address is a valid UK address at this stage.
- Apply online immediately, within the first 1–3 days.
- Identity verification — through a smartphone with an NFC scanner.
- Until you get your NI, your employer will use 1257L W1/M1 (if you are lucky) or BR.
- Important: do not lose the letter from DWP. Living conditions in caravans often lead to lost mail.
2. Student Visa
- Right to work: 20 hours/week during term, unlimited during holidays.
- The university does NOT apply for an NI for you — you do it yourself through gov.uk.
- If your yearly income is below £12,570, on BR you lose 20% of every £1.
3. Skilled Worker Visa
- An NI Number is often automatically generated when your visa is approved. It appears in your eVisa profile.
- Important: You can see your NINO in the eVisa itself, but you cannot share it through a share code. If your employer asks for your NINO, give it to them separately (in writing).
- If the NINO field in your eVisa is empty — apply manually through gov.uk with your CoS reference.
4. Family / Dependant Visa
- Standard gov.uk process. No special features.
- An NI is critical for self-employment registration, credit score, and renting (landlord credit check).
5. Asylum seeker / ARC holder
- Before 26 March 2026: Permission to Work was limited to Immigration Salary List roles (shortage occupations).
- From 26 March 2026 (HC 1691): those who have been waiting for a decision for >12 months (not their fault) can work in any role from Appendix Skilled Occupations at RQF Level 6+ (degree-level: doctor, engineer, scientist).
- Also from 2 March 2026: new asylum grants — only 30 months permission (instead of 5 years).
- Process:
- PTW1 form → Permission to Work Team (Level 0, Capital Building, Old Hall Street, Liverpool, L3 9PP).
- Approval — new ARC with note "WORK PERMITTED".
- NI Number application — separate helpline 0300 200 3500. You may need an in-person interview at a Jobcentre showing your updated ARC.
Emergency Tax — how to fix it
Check your payslip. Find the line Tax Code. If it says BR, 0T or 1257L W1/M1 — you are on emergency.
| Code | What it means | Amount taken | Action |
|---|---|---|---|
| 1257L | Standard cumulative | 0% up to £12,570/year; 20% above | Nothing, everything is OK |
| 1257L W1/M1 | Emergency non-cumulative | ~20% after £242/week, but allowance "burns" if you miss a week | HMRC will automatically switch to cumulative when they receive your data |
| BR | Basic Rate without allowance | 20% on all your salary | Urgently give your employer your NI Number or P45 |
| 0T | Zero allowance | 20% (40%/45% if you exceed the threshold) | Urgently give your employer your NI Number or call HMRC |
| K… | Negative allowance | Virtual income added to your salary | Anomaly — call 0300 200 3300 |
How to fix it
- Get your NI Number and give it to your employer → they will notify HMRC through RTI.
- Or call HMRC: 0300 200 3300 (with an interpreter). Say "I'm on emergency tax code, I want to switch to 1257L". You will need: name, date of birth, NI Number, employer name + Payroll ID (from your payslip).
- Or write a letter: HMRC, Pay As You Earn, BX9 1AS. Attach a copy of your payslip.
- Wait for the update — HMRC sends your employer form P6/P9. Usually 2–4 weeks until the tax code is changed.
- Overpaid tax is returned through your next salary (in-year repayment) — you do not need to apply separately.
Real waiting times for an NI Number
The stated SLA from gov.uk = 4 weeks after verification. In practice, during peak (April–August) delays are common.
| Visa | SLA | Real time | Delay factor |
|---|---|---|---|
| Seasonal Worker (peak Apr–Aug) | 4 weeks | 8–14 weeks | DWP overload, manual photo check |
| Skilled Worker | 0 (auto) | 0–5 weeks | Integration issues between eVisa and DWP |
| Family Dependant | 4–8 weeks | 10–16 weeks | Complex checks |
| Student | 4 weeks | 6–10 weeks | Standard |
| ARC + Permission to Work | 4 weeks | 8–12 weeks | Plus time for PTW1 review |
Source: gov.uk Performance Data + aggregated Reddit r/UKVisa, r/UKPersonalFinance threads 2025–2026.
12 unusual casesLetter did not arrive, lost it, two jobs, typo, repatriation — what to do
1. Letter did not arrive after 8 weeks
DO NOT create a duplicate application — the anti-fraud system will block both. Call 0800 141 2079 with your Application Reference Number. During peak (April–August) delays of 12–16 weeks are normal.
2. Lost the original letter
DWP does not generate a replacement. Alternatives: payslip, P60, HMRC App, Personal Tax Account on gov.uk. For a paper duplicate — form CA5403 (10 working days UK, 21 working days abroad). Phone disclosure is forbidden by security rules.
3. Old NI Number from a previous stay
Your NI Number is lifelong. If you come back after 5 years, your old NI is still yours. Submitting a new application is fraud. Give your old number to your new employer.
4. Two jobs at the same time
Main employer uses 1257L (full allowance), the second uses BR (20% on every £1). You can ask HMRC for a split allowance in a proportion (for example, £6,000 for job A, £6,570 for job B). This makes sense if you have fixed hours.
5. Left the UK before the letter arrived
Personal Tax Account is not available without an NI. The only way is to send form CA5403 by international post to HMRC (address on the form). Response time — 21 working days to a foreign address. On your P85, state that your NI is pending.
6. Payroll error in your NI Number
A typo in one letter (JC instead of JG) → RTI does not find a match → temporary TN reference → BR code. You will only notice it through a detailed payslip audit. Fix it through your employer's payroll: show the payslip with the typo and your original NI letter.
7. Retroactive adjustment after getting your NI
HMRC sends your employer form P6/P9: apply 1257L cumulative from 6 April. Overpaid tax is returned in the next pay cycle. A large bonus payment in your salary is your own money.
8. The "duplicate" phenomenon
Due to a system error, two NI Numbers are created. HMRC manually consolidates them — 4–8 weeks of account lock. Call HMRC and explain.
9. Change of surname (marriage)
Your NI Number does not change. Notify HMRC through Personal Tax Account → Report a change of name. Ignoring this will block your profile.
10. Automatic generation for 16–17 year olds
Only for UK residents whose parents receive Child Benefit. Does not apply to children of seasonal migrants (by Seasonal Worker visa rules, children must not be in the UK).
11. ARC + Right to Work after March 2026
HC 1691 (from 26 March 2026): asylum seekers with >12 months waiting can work in roles at RQF Level 6+. Process: PTW1 → new ARC "WORK PERMITTED" → NI through 0300 200 3500 (asylum-specific helpline) → possibly an in-person interview.
12. Final repatriation
You do not need to "close" your NI Number. P85 puts your profile into dormant status. If you come back after 10 years, your NI becomes active again.
Can you work without an NI Number?
Yes. An NI Number is an identifier for tax, NOT permission to work. UK law allows you to start work as soon as you have the Right to Work (eVisa share code, ARC with work permission).
Your employer MUST accept you and apply a temporary tax code. Refusing to hire you with the reason "you have no NI" is illegal. Refer to gov.uk: "You can start work before you have your NI number."
What will happen: your employer will assign a temporary Payroll Number and apply an emergency code (1257L W1/M1 or BR). When the letter with your NI arrives, give it to them. The tax code will be corrected and any overpaid tax will be returned.
P45 — take it when you leave a job (critical for P85)
P45 is an official document that your employer must give you when you leave or your contract ends. Without it, getting a tax refund through P85 becomes much more difficult.
| Field | What it means |
|---|---|
| Tax Code | Your tax code at the time you left |
| Total Pay to Date | Gross earnings since 6 April |
| Total Tax to Date | Income Tax deducted during the period |
| NI Number | Your NINO |
| Employer PAYE ref | Your employer's identifier in HMRC |
| Leaving Date | Date you left |
Structure of P45
- Part 1A — for you, keep it (at least 4 years).
- Part 2 + Part 3 — for your new employer, so they can apply the correct tax code immediately.
- Part 1 goes to HMRC automatically — you will not see it.
If your employer does not give you a P45 — remind them in writing (email). If they ignore you, complain to HMRC on 0300 200 3300 (with an interpreter). Many seasonal workers lose hundreds of pounds because they leave without a P45.
Lost your P45? Your employer is not required to give you a duplicate, but you can request a Statement of Earnings and check your data in Personal Tax Account on gov.uk.
How to get back overpaid tax
If you were on emergency tax (BR/0T) or worked only part of the year, HMRC must return the overpaid amount. 5 ways:
| Method | When | Time |
|---|---|---|
| Automatic | You are still working and have received your NI | Next salary (in-year repayment) |
| Personal Tax Account | You have a Government Gateway account | 5–6 weeks to a UK account via BACS |
| Call HMRC 0300 200 3300 | Any situation | 4–8 weeks |
| Form P50 | You stopped working but have not left the UK | 6–8 weeks |
| Form P85 | You have left the UK | 6–12 weeks, by paper cheque |
P85 — for those leaving. Full guide: /p85 — step-by-step instructions. Important: HMRC issues a P85 refund only by paper cheque (not bank transfer). The cheque is sent to a UK address or a nominee.
Example calculation: you worked 3 months on BR with a salary of £2,000/month. They deducted ~£400/month = £1,200. The correct tax for 3 months is ~£105. Overpayment: ~£1,095. This money will be returned.
Do not pay intermediaries. Tax refund agencies take 25–50% of the refund and may ask you to sign a Deed of Assignment (giving them control over the money). Everything can be done for free through gov.uk or by calling 0300 200 3300.
Top 5 scam schemes — be careful
- Telegram bots "fast NI Number for £200" — there is no fast track in DWP. Your money will be lost and your NI will not come faster.
- Phishing emails "HMRC needs NI verification" — HMRC never asks for your NI by email or SMS. Do not click links.
- Fake gov.uk websites — check the URL: gov.uk (with the tab "Crown copyright"). Services like service.gov.uk are official. .com / .org / .co.uk are scammers.
- Agency charging an "NI processing fee" — gov.uk is free. Any payment for applying = scam.
- Selling fake / stolen NI Numbers — a criminal offence for both sides. Working on someone else's NI = identity fraud.
25 frequently asked questions
How much does an NI Number cost?
Free. Any request for money is a scam.
How long do I wait for an NI Number?
gov.uk SLA = 4 weeks. Real times during peak (April–August): Seasonal Worker 8–14 weeks, Family 10–16 weeks, Student 6–10 weeks. Skilled Worker often gets it automatically when the visa is approved.
Can I work without an NI Number?
Yes. Right to Work is a separate document (eVisa, Share Code). Your employer cannot refuse you because you have no NI. They will apply an emergency tax code and correct it when you get your number.
What does tax code BR mean?
Basic Rate without personal allowance. 20% is taken from all your salary. Used when you have no NI/P45/Starter Checklist or for a second job. On £500/week = overpayment of £48.35/week compared to 1257L. For a 26-week season = £1,257.
What does tax code 0T mean?
Zero allowance, but it allows the higher rate (40%) when income is >£37,700. For a typical seasonal worker the effect is the same as BR.
What does 1257L W1/M1 mean?
Emergency cumulative code. The numerical effect is the same as normal 1257L, but it is non-cumulative — if you miss a week, the allowance "burns" instead of carrying over. Not critical with a steady salary.
How do I fix a wrong tax code?
Give your NI Number to your employer → they will notify HMRC through RTI. Or call 0300 200 3300 (with an interpreter). HMRC sends your employer form P6/P9, update in 2–4 weeks.
Where can I find the phone number for an NI Number?
England / Scotland / Wales: 0800 141 2079 (Mon–Fri 8:00–17:00). Northern Ireland: 0800 587 0024. Asylum seekers: 0300 200 3500.
What if I lost my NI letter?
DWP does not send a replacement. Find your NI: payslip, P60, HMRC App, Personal Tax Account. Paper duplicate — form CA5403 (10 working days UK / 21 abroad). Phone disclosure is forbidden.
Is an old NI from a previous stay still valid?
Yes. Your NI is lifelong. Submitting a new application is fraud. Give your old number to your new employer.
Two jobs at the same time — how does the tax code work?
Main employer — 1257L. Second — BR (20% on everything). You can ask HMRC for a split allowance based on actual hours.
Does my NI Number change when I marry?
No. It is lifelong. Notify HMRC about a name change through Personal Tax Account.
Can I apply with an ARC?
Only after you get Permission to Work (PTW1 form). From 26 March 2026 — RQF Level 6+ roles (HC 1691). After approval — new ARC, NI through 0300 200 3500.
Skilled Worker — do I need to apply for an NI?
Often the NINO is automatically generated and appears in your eVisa. If the field is empty — apply manually through gov.uk with your CoS reference.
Can I share my NI through an eVisa share code?
No. The NINO is visible in your eVisa profile, but the share code does not include it. Give your employer the NINO separately.
What if my passport does not have an NFC chip?
Digital verification is not possible. The system will send you instructions by email: either postal verification (certified copies) or an in-person interview at a Jobcentre. +3–4 weeks to the waiting time.
What should I write as my UK address if I live in a caravan?
Use the camp address on the farm (where you currently live in the UK). This is valid. For your home address (for P85) — write it in Latin letters, as detailed as possible.
What is NIC and how much do I pay?
National Insurance Contributions — mandatory payments for State Pension and social insurance. 2026/27: 8% between £242/week and £967/week; 2% above. On £500/week = £20.64/week NIC.
What is P45 and why do I need it?
A document from your employer when you leave: gross pay, deducted tax, NI Number, tax code. Give it to your new employer (Parts 2&3) to avoid BR. Critical for digital P85 submission.
What if my employer does not give me a P45?
Send a written reminder (email). If they ignore you, complain to HMRC on 0300 200 3300. You can also request a Statement of Earnings on the company letterhead.
How do I get back overpaid tax without intermediaries?
5 ways: automatic (through NI on the farm), Personal Tax Account on gov.uk, call HMRC 0300 200 3300, form P50 (if you stopped working in the current year), form P85 (if you left).
Should I pay an agency for a refund?
No. They take 25–50% + a Deed of Assignment gives them control over the money. Through gov.uk it is free and takes 20 minutes.
How does HMRC issue a P85 refund?
Only by paper cheque to a UK address (or nominee). Not bank transfer. This has always been the case — it is not a new rule for 2026. The cheque is valid for 6 months. More details: /p85.
I left the UK forever — do I need to "close" my NI?
No. It does not close. P85 puts your profile into dormant status. If you come back after years, the same NI becomes active again. The history accumulates forever.
Is the NI Number visible on the eVisa?
Yes, if the NINO was generated when your visa was approved. It is displayed in the profile. But it is not shared through the share code.