Flu on booked Christmas leave: can you take those days later?

Flu does not become a holiday because the rota says you are off. If you were too ill to work during booked Christmas leave, you can ask to record the overlapping days as sickness and take the holiday later. Tell your employer now. The catch is pay. Unless your employer’s sick-pay scheme protects your earnings, saving the holiday can mean less money this month.

What to do while you are still ill

The switch is not automatic. GOV.UK says you can take the time as sick leave if you are ill just before or during holiday. You have to report it.

1. Follow the sickness-reporting procedure now. Give the dates you were too ill to work and say they overlap booked leave. Send written confirmation even if the policy requires a phone call. Agency staff should notify the agency and follow any reporting requirement at the workplace too.
2. Provide the right evidence. Self-certify for an illness lasting seven calendar days or fewer. If it lasts longer, obtain a fit note covering the absence. Weekends and bank holidays count. For SSP, report by your employer’s deadline or within seven days if it has none. Late reporting can cost sick pay.
3. Ask for the days back. Request written confirmation of your holiday balance, your leave-year end and which part of your entitlement the restored days belong to. Keep the booking, rota, sickness messages and payslips somewhere you can access outside work.
4. Request replacement dates. If the leave year is about to end, ask about carry-over at the same time. Do not wait for a grievance to finish before checking a tribunal deadline.

Use the evidence option that fits your absence. If you have already returned to work, send the request now and explain any delay. Do not assume a missed reporting deadline means you should abandon the holiday claim.

The days you were too ill to work come back

This right concerns holiday you could not take because you were ill. It is separate from the right to SSP from the first qualifying sick day, which changed on 6 April 2026.

Acas explains that you can report sickness during holiday, receive sick pay if eligible and keep the holiday for another time. Statutory holiday rights cover employees and other workers, including agency workers. Genuinely self-employed people do not have those rights. A contract or app calling you “self-employed” does not settle your legal status.

Only the overlap comes back. If you recover before your booking starts, none of the holiday was lost to illness. If you fall ill halfway through it, the earlier days remain holiday. Statutory holiday also keeps building up while you are off sick. Sickness can still count under an absence policy; see what to do about sickness warnings.

Five days in bed do not necessarily mean five holiday days back. This example separates the booked shifts from the weekend.

What proof you need and what happens to pay

Count the whole illness in calendar days, not shifts. For seven days or fewer, GOV.UK says you do not need a fit note or other medical proof. Your employer can ask you to self-certify, for example by completing its form. For more than seven consecutive days, get a fit note. A doctor, registered nurse, occupational therapist, pharmacist or physiotherapist can issue one after assessing you. It is free if you have been ill for more than seven days when you ask.

From 6 April 2026, in Great Britain and Northern Ireland, SSP is £123.25 a week or 80% of average weekly earnings, whichever is lower. There are no waiting days or lower earnings threshold. Eligible employees can receive it from the first full qualifying day of sickness, for up to 28 weeks. Qualifying days are normally your working days. A non-working Saturday counts towards the fit-note clock but does not earn SSP. Check eligibility and the earnings calculation in our SSP guide.

Converting holiday to sick leave does not give you full holiday pay and SSP twice for the same dates. GOV.UK says SSP counts towards holiday pay already received. Ask payroll to set out how it will adjust any advance payment. Check your contractual sick-pay scheme too. The restored leave remains available, with holiday pay when you take it unless it has already been lawfully paid through rolled-up holiday pay.

Christmas Day, Boxing Day, and the shutdown

In 2026, Christmas Day is Friday 25 December. Boxing Day falls on Saturday, so the substitute is Monday 28 December, in England, Wales, Scotland and Northern Ireland. New Year’s Day 2027 is Friday 1 January. Scotland also has Monday 4 January for 2 January. GOV.UK lists them.

Your employer can include bank holidays within the statutory 5.6 weeks. If it deducted Christmas Day or substitute Boxing Day from your holiday balance and you were too ill to work, include those dates in your request to convert the booking. If a bank holiday did not use any holiday entitlement, there is no statutory day to restore. For bank holidays provided as contractual extras, check the contract. A Christmas shutdown does not remove the sickness issue just because everyone was told to book leave. See working at Christmas for the wider bank-holiday rules.

Two examples, including the cash shortfall

These are worked examples, not accounts from named workers. Both assume SSP-only sick pay, prompt reporting and the same normal earnings throughout the relevant earnings period. All sums are before deductions.

Your employer can refuse dates, not the entitlement

You cannot simply announce that the restored days will be taken in January. Under the default regulation 15 rules in Great Britain, your notice must be given before the date that is twice as many days ahead of the first requested day as the number of days requested. An employer refusing dates must notify you before the date that is as many days ahead as the leave requested. Allow an extra clear day rather than cutting it fine. A relevant agreement, including an enforceable contractual term, can change these rules.

The employer can also require leave on particular dates, using the longer notice rule unless an agreement changes it. But refusing every usable date is different from refusing one busy week. Statutory leave cannot be replaced by cash while the job continues. Payment for untaken statutory leave is due when employment ends. Lawful rolled-up holiday pay pays for the leave in advance; it does not buy away the right to time off.

If the leave year is about to end

Find your leave-year dates in the contract, handbook or collective agreement. Do not assume they follow the calendar year. For a regular five-day week, the statutory 5.6 weeks amounts to 28 days, split into four weeks and an additional 1.6 weeks.

Regulation 13(15) protects leave you were unable to take because of sick leave. It does not specify a minimum sickness duration. A short illness at the end of the leave year can therefore matter. The condition is that sickness prevented you taking the leave within that year. A bout of flu with months left does not automatically let you postpone the days beyond year-end.

A leave year ending on 31 December 2026 gives a sickness carry-over deadline of 30 June 2028. One ending on 31 March 2027 gives 30 September 2028. Ask which statutory portion your restored days belong to rather than assuming every day qualifies. GOV.UK confirms the wider protection for irregular-hours and part-year workers.

Separate employer-failure rules can protect the four-week portion where the employer did not recognise the right to paid leave, provide a reasonable opportunity and encouragement to take it, or warn that it would otherwise be lost. That carry-over is not subject to the sickness rule’s 18-month cap. It ends after the first full leave year in which the employer has put the failure right. If every request was blocked, see what happens when your boss refuses all your holiday requests.

Northern Ireland and Scotland

Sick pay matches. From 6 April 2026 the Labour Relations Agency confirms day-one SSP, no earnings floor, and the same rate. HMRC still decides SSP disputes.

Agency, zero-hours, and the label on the app

A zero-hours contract does not by itself remove holiday rights or SSP eligibility. Agency staff should ask the agency to correct the holiday balance and pay record. Genuinely self-employed people have neither statutory paid holiday nor SSP, although benefits may be available. Get advice if the label on your contract does not match the way you work.

For Great Britain leave years beginning on or after 1 April 2024, qualifying irregular-hours and part-year workers accrue statutory holiday at 12.07% of hours worked in each pay period. They continue accruing during sickness under a separate averaging calculation. Employers can use rolled-up holiday pay for these workers, calculated as 12.07% of total pay and shown separately on the payslip, in addition to normal wages.

If you receive lawful rolled-up pay, restoring the time does not necessarily mean another payment when you take it. The holiday pay may already have been paid. Ask the agency which hours it has restored and how it calculated holiday pay during sickness. Being agency staff does not itself make rolled-up pay lawful. These GB reforms should not be applied to Northern Ireland. See our agency workers’ guide.

If your employer refuses to correct the balance

Ask for the refusal and its reasons in writing. You do not need to resign to pursue the days or pay. If your visa depends on this employer, seek advice before taking a step that could put your job at risk.

1. Ask for a correction. Put the booking beside the sickness dates. Ask for the restored balance and the sick-pay calculation. If that fails, raise a formal grievance with help from your union or an adviser.
2. Separate the disputes. Refused holiday or unpaid holiday pay can lead to a tribunal claim. An SSP entitlement dispute goes to HMRC’s Statutory Payment Disputes Team. Ask payroll to explain any difference between SSP and contractual sick pay.
3. Protect the tribunal deadline. For most GB holiday and wages claims with a relevant date on or after 1 October 2026, the limit is six months minus one day. Earlier relevant dates usually retain three months minus one day. For refused leave, the relevant date is generally when leave should have begun, not simply when a manager sent a refusal. For unpaid wages, it is normally the payday. Acas explains the change; SI 2026/954 sets the transition. Northern Ireland generally retains three months minus one day. Get the exact date checked.
4. Notify early conciliation in time. Use Acas in Great Britain or the Labour Relations Agency in Northern Ireland. A timely notification can pause the clock. A grievance or a call asking for advice does not. See our tribunal time-limits guide.

Your workplace union representative is a useful first contact. Usdaw represents retail workers; UNISON covers many care and NHS support roles; Unite and GMB organise across hospitality, logistics and other sectors. Ask what help is available for an existing dispute. You can also seek advice from Acas, Citizens Advice or a law centre. In Northern Ireland contact the Labour Relations Agency.