Two of your team have asked for the same week off in December. You can spare one of them. You cannot spare both.

The instinct is that saying no is the risky part. It is the wrong way round. Regulation 15(2)(b) of the Working Time Regulations 1998 lets an employer require a worker "not to take such leave" on particular days. A statutory power, not a grey area. Acas expects a good business reason behind it, and a better one if flights are already booked. But the reason is rarely what goes wrong. The power comes with a clock attached, which is why a reasonable decision taken in mid-December can already be out of time.

The August accrual maths raised this and walked past it: if two of your three baristas want the same week, you need to know early. (Regulations: Great Britain. Bank holiday dates: England and Wales.)

The counter-notice, and one date

Reg 15(4)(b) sets the ratio: a refusal must be given as many days before the first day of leave as there are days being refused. One for one.

Reg 15(3)(c) adds the word that catches everybody: the notice must land before that date, not on it, which is why GOV.UK renders it as the leave requested "plus 1 day", giving 11 days' notice to refuse 10 days' leave.

The week in question: Sunday 20 to Saturday 26 December 2026

Count the days. (26 minus 20) + 1 = 7 days.
Count back seven days to 13 December, then go one earlier, because the notice must land before it: Saturday 12 December 2026.
Cross-check. 7 + 1 = 8, and 20 minus 8 = 12 December.

Now the version that actually happens. It is busy, the conversation gets postponed, you answer on Tuesday 15 December. Notice given: 20 minus 15 = five days. Required: eight. Three days short. You were not wrong to refuse. You were three days late doing it.

Your contract probably beats every word of that

Reg 15(5) says any right or obligation in paragraphs (1) to (4) "may be varied or excluded by a relevant agreement", and reg 2(1) includes "any other agreement in writing which is legally enforceable" between worker and employer. For most cafés that means your contract or a holiday policy. GOV.UK agrees: if the contract says something different about notice, it applies.

Not a floor, then, but the default for anyone who never wrote anything down, and writing your own is lawful, not a dodge. A policy closing December requests on 31 October, with answers out on 7 November, brings the question forward. Without one, someone can ask on 5 December and leave you seven days to decide. Reg 15 covers the statutory 5.6 weeks only; contractual holiday above that runs on the contract alone.

The two notices worth sending this month

A blackout is a refusal sent before anyone asks

GOV.UK confirms employers can "restrict when leave can be taken, for example at certain busy periods". Same instrument, same one-for-one ratio, counted from the first blacked-out day.

Block 18 to 31 December: (31 minus 18) + 1 = 14 days. 18 minus 14 = 4 December, and the notice must land before that: Thursday 3 December.

One wrinkle: GOV.UK does not separate restricting leave from requiring it, giving twice the length across that section, which would mean 19 November.

Send it instead on Tuesday 22 September: 8 left in September + 31 + 30 + 18 = 87 days of notice, against a floor of 15 on one reading, 29 on the cautious one. Either way you are three times clear.

A shutdown is a different instrument, and stricter

Telling staff to take leave, rather than not to, is reg 15(2)(a), and reg 15(4)(a) doubles the ratio.

Close Saturday 26, Sunday 27 and Monday 28 December: (2 x 3) + 1 = 7, so notice by Saturday 19 December.

Then check the calendar. Christmas Day 2026 is a Friday and 26 December a Saturday, so the Boxing Day bank holiday moves to Monday 28 December. If your contract reads "plus bank holidays", that is a paid day off you have already named and cannot charge to annual leave as well. You are requiring two days, not three: (2 x 2) + 1 = 5, so notice by 21 December. That one word, "plus" or "including", settles it.

What you are doing	Notice you owe	December 2026
Refusing a request	The days of leave, plus one	7 days from Sun 20 Dec, say no by Sat 12 Dec
Declaring a blackout	Same, from the first blacked-out day	18 to 31 Dec is 14 days, notify by Thu 3 Dec
Requiring a shutdown	Twice the days, plus one	26 to 28 Dec is 3 days, notify by Sat 19 Dec
A worker asking for leave	Twice the leave, plus one	7 days from Sun 20 Dec, ask by Sat 5 Dec

The mistake is not saying no, it is saying it differently to different people

"First come, first served" is not the legal default. Reg 15 contains no allocation rule. Rotation year to year, seniority, a ballot, splitting the week: all lawful. What is not safe is deciding it fresh each December with a different reason, because the reason has to survive being put next to last year's.

Acas is explicit that time off for religious festivals must not take priority over other reasons: that can discriminate against people with no religion or belief, itself protected. In its worked example, a manager cancels one employee's booked holiday to free the date for another's festival: likely direct discrimination against the person cancelled.

What a written rule needs to contain

Acas advises asking staff to book well in advance, and agreeing up front how to handle too many wanting the same week. Not a clause to paste in, then, but six things to decide and check against your own contracts:

The request window
The decision date you will answer by
The allocation rule when two land on the same week
The maximum off at once, per site and per role
The blackout dates
The carry-over treatment at leave year end

That last one has a catch. The 1.6 weeks above the four-week core carries into the next leave year only if a relevant agreement provides for it. One exception: reg 13A(7A) carries it forward automatically where statutory leave, maternity included, stopped the worker taking it. Otherwise, no clause, no carry-over.

What over-refusing costs you in January

There is a hard limit. GOV.UK: employers can refuse leave at a certain time, but not refuse to let workers take it at all. Reg 13(9)(a) says the four-week core can normally only be taken in the leave year it is due, so on a calendar leave year a December blackout leaves those days nowhere to go. Then reg 13(16) and (17): where you failed to give a reasonable opportunity to take the leave, or to say it would be lost, the worker carries it forward.

Refusing too much does not delete the leave. It moves the bill.

Illustrative figures, not mine. A leave year of 1 January to 31 December, one full-timer on 40 hours at the April 2026 National Living Wage, £12.71 an hour.

Say 40 hours of the 5.6 weeks untaken on 31 December, carried into January
Base pay: 40 x £12.71 = £508.40
Employer NI at 15%: £508.40 x 0.15 = £76.26
Employer pension at 3%: £508.40 x 0.03 = £15.25
Total: £599.91

Three people each carrying a week is 3 x £599.91 = £1,799.73, roughly £1,800 of January wage cost created in December, on top of the cover you still pay for. Check your own leave year: absent a written agreement it starts on each worker's start date.

The Employment Rights Act 2025 did not touch reg 15. A Working Time claim over anything you do from 1 October 2026 gets six months to reach a tribunal, not three, so a December refusal is caught.

Twenty minutes this week

Pull December's trade curve off the till and decide which days cannot lose a person. At roughly 20 covers per staff hour, the demand-based rota method turns that into headcount.
Write the blackout dates down. Named days, not "the run-up".
Send one message to everyone on the same day, with the same rule, the request deadline and the decision date in it.
Keep the answer in writing. Reg 16B, inserted by section 35 of the Employment Rights Act 2025, has required annual leave and holiday pay records since 6 April 2026, kept six years. It does not demand a log of refusals, but a dated answer shows you gave a real opportunity to take the leave.
Build the rota against it. If you lined up summer staff to return in December when you closed out the seasonal contracts, this is the other half of that.

Most of the pain comes from the answer living in three places: a contract in a drawer, a rota on the wall, a balance in someone's head. StaffBrik keeps the rota, time-off requests and balances in one place, and a spreadsheet with one row per person does the same job.

The notice period is only frightening in December. In September it costs you a group message.

Ed O'Brien has run Hunters Cake Company for 17 years across cafés in Witney, Burford, and a bakery in Carterton, Oxfordshire. He's building Brikly - modular tools that give independent café owners the same data the big chains have, without the big chain price tag.