Starting a new job without your P45 typically means one thing: emergency tax. Your new employer has no choice but to use a temporary tax code that often results in higher deductions from your first few pay packets.
Some people lose hundreds of pounds to emergency tax simply because a P45 arrived late, went missing, or was never issued at all.
This guide explains why P45 problems happen, what emergency tax actually costs you, and the steps to take when your previous employer will not cooperate.
Understanding these issues helps you act quickly to minimise overpaid tax and recover money already lost.
Key Takeaways
- Without a P45, your new employer must use an emergency tax code that may ignore your personal allowance
- Emergency tax on a £30,000 salary could mean paying £500 or more extra per month until resolved
- Employers face penalties for not providing P45s, but enforcement is limited in practice
- The Starter Checklist can replace a missing P45 and help your new employer set the correct tax code
- HMRC’s personal tax account shows your P45 information even if you never received the physical document
- You can reclaim emergency tax overpayments for up to four years after the tax year in question
Why Your P45 Matters So Much
The P45 is the document that carries your tax information from one employer to the next.
It tells your new employer your tax code, how much you have earned so far this tax year, and how much tax you have already paid.
Without this information, your new employer cannot calculate your tax correctly.
When you start a new job, your employer needs to know whether you have already used some or all of your tax personal allowance with a previous employer.
If you earned £10,000 and paid £0 tax because it fell within your £12,570 personal allowance, your new employer needs to know this.
Otherwise, they might give you another full personal allowance, leading to underpaid tax, or they might assume the worst and tax you as if you have no allowance at all.
The P45 solves this problem by providing a snapshot of your tax position at the moment you left your previous job.
Your new employer enters these figures into their payroll system, and HMRC’s records update accordingly.
The system works smoothly when P45s flow correctly between employers.
Problems arise when this chain breaks:
- A delayed P45 means your new employer operates blind for your first few pay periods
- A lost P45 means you cannot prove your previous earnings and tax payments
- An incorrect P45 means wrong information enters the system and follows you until corrected
How Emergency Tax Codes Work
When your new employer does not have your P45, they must make assumptions about your tax position.
HMRC provides specific rules for these situations, and they generally err on the side of collecting more tax rather than less.
The most common emergency codes are 1257L W1, 1257L M1, or simply BR.
The W1 and M1 suffixes mean your employer calculates tax on a week-by-week or month-by-month basis without considering your cumulative position for the year.
This non-cumulative approach often results in higher tax because it does not account for any unused personal allowance from earlier in the tax year.
The BR code is more aggressive—it applies basic rate tax (20%) to your entire salary with no personal allowance at all.
This code is typically used when HMRC believes you have another job using your personal allowance, or when they have no information about you whatsoever.
Example: The Real Cost of Emergency Tax
Consider someone earning £2,500 per month who starts a new job in July without a P45.
Under a normal cumulative 1257L code, their first pay would be largely tax-free because they would have four months of unused personal allowance (around £4,190) to set against their earnings.
Under an emergency W1/M1 code, they might pay tax as if only one month’s allowance (around £1,048) applies, resulting in tax on approximately £1,452 rather than £0.
The difference in take-home pay can be substantial. On a £30,000 annual salary, emergency tax could cost an extra £200 to £500 per month compared to the correct tax code.
Over several months, this adds up to a significant sum sitting with HMRC that rightfully belongs in your pocket.
Common Reasons P45s Go Missing
Understanding why P45 problems occur helps you anticipate and prevent them.
- Timing gaps between leaving and starting – Your old employer cannot generate your P45 until after your final pay has been processed. If you leave on a Friday and start your new job the following Monday, the P45 simply will not exist yet. Most payroll systems run weekly or monthly, so the P45 might not be ready for days or even weeks after you leave.
- Employers who close or go into administration – The normal payroll processes stop, and P45s may never be issued. Even if an administrator eventually handles outstanding payroll matters, it can take months. Meanwhile, former employees struggle to prove their earnings and tax position.
- Small employers with informal processes – They may not understand their legal obligations, or they may have inadequate payroll systems. Some employers mistakenly believe P45s are optional or only required if the employee asks.
- Disputes between employer and employee – Some employers wrongly withhold P45s as leverage in disagreements about final pay, holiday entitlement, or other matters. This is not lawful—employers must provide P45s regardless of any disputes—but it happens nonetheless.
- Administrative errors – The document might be sent to an old address, emailed to a defunct inbox, or simply lost in the post. Digital P45s can end up in spam folders or be overlooked among other leaving documentation.
- Agency and zero-hours workers – Multiple short assignments mean multiple P45s, and keeping track becomes difficult. Some workers never receive P45s for brief assignments, or receive them long after starting their next role.
What To Do When Your Employer Will Not Provide a P45
If your previous employer refuses or fails to provide your P45, you have several options:
- Make a formal written request – Email your former employer’s HR or payroll department specifically asking for your P45. Keep a copy of this request. If they claim it has already been sent, ask them to confirm when and how it was sent, and request they send a replacement.
- Escalate if the initial request fails – Employers have a legal obligation to provide P45s and can face penalties from HMRC for non-compliance. Let your former employer know you are aware of this obligation. Sometimes a reminder of the legal position prompts action.
- Contact HMRC – HMRC can contact the employer directly, and in some cases can reconstruct your P45 information from Real Time Information (RTI) data that employers submit with every payroll run. Call the HMRC employer helpline or use your personal tax account to report the issue.
- Ask for a Statement of Earnings – If a P45 genuinely cannot be provided—perhaps the employer has ceased trading—a statement of earnings on company letterhead showing your total pay and tax deducted can serve a similar purpose. Your new employer can use this information to set up your payroll record.
- Use your personal tax account – HMRC’s online service shows your employment income and tax paid, updated in near real-time through RTI. You can access this information even without ever receiving a physical P45. Share a screenshot or printout with your new employer to help them understand your tax position.
The Starter Checklist: Your P45 Alternative
When you cannot provide a P45, your new employer should give you a Starter Checklist (formerly known as a P46) to complete.
This form collects the information needed to set your tax code correctly.
The Starter Checklist asks three key questions about your employment situation:
- Statement A – This is your first job since 6 April and you have not received any taxable benefits such as Jobseeker’s Allowance or Employment and Support Allowance. Selecting this tells your employer to give you a full personal allowance on a cumulative basis.
- Statement B – This is your only job but you have had another job or received taxable state benefits since 6 April. Your employer will still give you the standard personal allowance but on a non-cumulative (week 1/month 1) basis until HMRC provides your correct code.
- Statement C – You have another job or receive a state pension. This tells your employer not to apply any personal allowance because it is being used elsewhere.
Choosing the correct statement is crucial. Selecting Statement A when Statement B or C applies could result in underpaid tax and a bill later.
Selecting Statement C when Statement A applies means unnecessary emergency tax deductions.
Complete the Starter Checklist as soon as possible—ideally before your first pay date. The sooner your employer has this information, the sooner they can apply an appropriate tax code.
Delays can mean more pay periods under emergency tax.
Checking Your P45 for Errors
Receiving a P45 does not guarantee accuracy. Errors on the document flow through to your new employer and can cause ongoing problems.
Check the following:
- Personal details – Your name, national insurance number, and address should all be correct. Errors in the national insurance number are particularly problematic because they can disconnect your earnings from your tax record entirely.
- Leaving date – Verify this matches your actual last day of work. This date determines which tax year your final earnings fall into if you leave near 5 April. An incorrect date could affect your tax position in either the old or new tax year.
- Pay and tax figures – The ‘total pay to date’ should match your gross earnings for the tax year up to your leaving date. Compare this to your final payslip, which should show year-to-date figures. The ‘total tax to date’ should match the income tax deducted from your salary (not including National Insurance, which is not shown on P45s).
- Tax code – This should match the code that appeared on your recent payslips. If it looks unfamiliar or includes unexpected suffixes like W1 or M1, this could indicate problems that will carry forward.
- Previous employment figures – If this was not your first job of the tax year, your P45 should include cumulative figures from earlier employments. If you had two jobs before this one, the P45 from your most recent job should show combined totals.
If you find errors, contact your former employer immediately. They should issue a corrected P45. Keep the incorrect version as evidence in case of disputes.
If your employer will not correct genuine errors, report the matter to HMRC.
Multiple P45s in One Tax Year
Changing jobs several times within a tax year creates additional complexity.
Each time you move, you should receive a P45 and pass it to your next employer. The cumulative figures should build correctly through the chain.
Problems arise when this chain breaks. If you lose one P45 in a sequence, subsequent employers lack accurate cumulative information.
You might be taxed correctly by each employer individually while your overall position is wrong.
Keep copies of every P45 you receive. Digital copies are acceptable—photograph or scan them as backup.
If you later need to prove your earnings and tax payments, these records become invaluable.
When starting a new job after multiple moves, ensure your latest P45 shows correct cumulative figures for the entire tax year, not just the most recent employment.
If the figures look too low (perhaps they only cover one job when you had two), raise this with your new employer immediately.
At tax year end, your P60 from your current employer should show total earnings and tax for the full year across all employments. Compare this to your records.
If the P60 only reflects your current job, HMRC may not have linked your earlier employments correctly.
P45s from Pension Providers
When you start receiving a pension, you receive a P45 from your pension provider just as you would from an employer. This P45 shows your pension income and tax deducted.
Pension P45s follow the same rules as employment P45s.
If you start a new job while receiving a pension, give both P45s to your new employer. They need to understand your complete income picture to apply the correct tax code.
Pension Lump Sum Withdrawals
Common issues arise when people draw pension lump sums.
Pension providers often apply emergency tax to lump sum withdrawals, resulting in significant over-deductions. You may receive a P45 showing these emergency tax amounts.
Claiming back the overpaid tax typically requires form P55 or P53 depending on your circumstances.
Multiple Pensions
If you have multiple pensions from different providers, you may receive multiple P45s.
Each provider taxes your pension as if it is your only income source. This can result in under-taxed or over-taxed positions depending on your total income.
State Pension
State Pension does not come with a P45 because it is paid gross without tax deduction. However, it is still taxable income.
HMRC should adjust your tax code to collect the tax due through your other income sources, but this does not always happen correctly.
Recovering Emergency Tax Overpayments
If you paid emergency tax, you should eventually receive the overpayment back—but ‘eventually’ can mean waiting until HMRC reconciles your tax position after the tax year ends.
Getting Your Money Back Faster
For faster recovery, ensure HMRC has correct information as soon as possible.
Once your new employer receives your P45 or Starter Checklist, they inform HMRC through RTI. HMRC should then issue a correct tax code.
Your employer will apply this code and refund the overpaid tax through your salary—you should see a larger than normal pay packet as the excess tax comes back.
If Automatic Correction Does Not Happen
If automatic correction does not happen within a few pay periods, contact HMRC directly.
Use your personal tax account to check whether they have received correct information about your employments. If the data looks wrong, call or write to explain your situation.
Claiming for Previous Tax Years
Claiming back for previous tax years requires more formal action.
You can claim overpaid tax for up to four years after the tax year in question. For 2021/22, the deadline is 5 April 2026.
Use HMRC’s online services or write to them explaining the emergency tax situation and requesting a refund.
Keep Your Evidence
Keep all documentation:
- Payslips showing emergency tax deductions
- P45s (or evidence you requested but did not receive them)
- Correspondence with employers
- HMRC communications
This evidence supports your claim if questions arise.
Preventing P45 Problems
Taking proactive steps reduces the chance of P45 difficulties affecting you:
- Before leaving a job, confirm how and when you will receive your P45 – Ask whether it will be posted, emailed, or available through an employee portal. Provide an address where you can definitely receive post, and an email address you check regularly.
- Allow realistic timing between jobs if possible – Giving your old employer a week to process your final pay and generate your P45 before you start elsewhere can prevent the emergency tax scenario entirely.
- Keep personal records throughout each tax year – Save every payslip, note down earnings and tax paid, and track your cumulative position. If your P45 goes missing, you can still provide your new employer with accurate information.
- Set up a personal tax account with HMRC – This gives you direct access to your tax information regardless of what documents you receive from employers. You can monitor your tax code, check your earnings are correctly recorded, and spot problems early.
- Understand your rights – Employers must provide P45s—it is not optional. If an employer refuses, you have routes for escalation. Knowing this puts you in a stronger position to insist on receiving what you are legally entitled to.
When Emergency Tax Is Correct
Not every emergency tax deduction is an error. In some situations, HMRC intentionally restricts your tax code because of concerns about your tax position:
- Underpaid tax in previous years – HMRC may issue a code that collects the arrears through reduced personal allowance. This can look like emergency tax but is actually intentional recovery of money owed.
- Multiple income sources exceeding higher rate thresholds – HMRC may remove personal allowance from one source to ensure correct overall taxation. The coding notice from HMRC should explain why your allowance has been reduced.
- Suspected tax avoidance – If HMRC suspects your employer is operating a tax avoidance scheme, they may issue restrictive codes to protect revenue while they investigate. This is rare but does happen.
Before assuming your tax code is wrong, check your personal tax account for any notices from HMRC.
If they have deliberately restricted your code, simply providing a P45 will not change it.
You may need to address the underlying issue—perhaps agreeing a payment plan for arrears or confirming your multiple income sources are correctly recorded.
What Employers Get Wrong About P45s
Understanding common employer errors helps you spot and address problems:
- Believing P45s are only required if requested – This is incorrect. P45s must be provided automatically when employment ends, without the employee having to request one.
- Withholding P45s until disputes are settled – Some employers think they can withhold P45s until all company property is returned or disagreements are resolved. This is wrong. The P45 obligation exists regardless of any other matters between employer and employee.
- Issuing informal leaving letters instead – Small employers sometimes issue letters stating your earnings and tax rather than proper P45s. A letter is not a P45 and will not be accepted by your new employer as such. However, it may serve as a Statement of Earnings if a proper P45 cannot be obtained.
- Forgetting previous employment figures – If you joined them mid-year with a P45 from an earlier job, your leaving P45 should show combined cumulative figures, not just what you earned with them.
- Payroll errors producing wrong figures – Transposing digits, using the wrong tax code, or showing incorrect dates. Always verify P45 information against your own records.
P45 FAQs
Q1: How long does an employer have to provide a P45 after you leave?
A: There is no specific deadline in legislation, but HMRC expects employers to provide P45s promptly after the final pay has been processed. In practice, this usually means within a few days to two weeks of your leaving date. If you have not received your P45 within a month, chase your former employer and consider reporting the matter to HMRC.
Q2: Can HMRC give me a copy of my P45 if I never received one?
A: HMRC cannot issue a replacement P45 document, but they hold the same information through Real Time Information submissions from employers. You can view your earnings and tax paid through your personal tax account online, and share this information with your new employer as evidence of your tax position.
Q3: What is the difference between tax codes 1257L, 1257L W1, and BR?
A: 1257L is the standard cumulative code giving you the full £12,570 personal allowance spread across the year. 1257L W1 or M1 gives the same allowance but calculated week-by-week or month-by-month without cumulative adjustment—often resulting in higher tax early in the year. BR applies basic rate tax (20%) to all earnings with no personal allowance.
Q4: How do I claim back emergency tax I paid because of P45 problems?
A: If you are still employed, your employer should refund emergency tax through payroll once HMRC issues the correct tax code. If you have left employment or the tax year has ended, contact HMRC directly through your personal tax account or by phone to request a refund. You can claim for up to four years after the tax year in question.
Q5: Do I need a P45 if I am starting my very first job?
A: No. First-time workers will not have a P45 because they have no previous employment. Complete the Starter Checklist selecting Statement A (first job since 6 April with no taxable benefits). Your employer will give you a full personal allowance on a cumulative basis from the start.
