Flexible Working as a Default Right: What UK Employers Must Do Now

Last updated: September 2026

Sarah runs HR for a distribution company in Leeds. Last Tuesday, the warehouse supervisor submitted a statutory flexible working request -- she wants to shift her start time from 7am to 9am three days a week to do the school run. Sarah reached for the standard refusal letter, ready to cite "inability to reorganise work" and leave it at that. Then a colleague stopped her: "Aren't the flexible working rules changing in a few weeks?"

They are. Sarah's standard letter would not survive what is coming. The Employment Rights Act 2025 flexible working provisions are arriving this Autumn, and the gap between what most employers currently do and what the new rules require is significant.

This guide covers exactly what is changing, how the reasonableness test works in practice, and what you need to have in place before the commencement date.

What Is the Flexible Working Default Right Change?

The ERA 2025 does not make flexible working an automatic entitlement. That is a persistent misunderstanding, driven by the government's original Make Work Pay language around a "genuine default". What the Act actually does is shift the burden on employers when refusing a request.

EmployerKit's analysis of the Act and the April 2026 government consultation confirms the core change: employers can only refuse a flexible working request if it is reasonable to do so on one of the eight statutory grounds. Simply citing a ground is no longer enough.

The eight grounds themselves do not change. What changes is the standard you must meet when relying on them.

Before and After: How the Standard Shifts

Requirement	Current rules	ERA 2025 (Autumn 2026)
State a refusal ground	Required	Required
Explain why refusal is reasonable	Not required	Required
Document the decision-making process	Best practice	Expected by tribunals
Explore alternatives before refusing	Recommended	Must demonstrate
Employee can challenge vague refusals	Difficult	Much easier
Written outcome with full reasoning	Not required	Required
Tribunal burden on employer	Low	Materially higher

The practical effect: a one-line letter citing "detrimental impact on quality" will not hold up. You need specific facts, a documented assessment, and evidence you considered alternatives.

The 8 Statutory Refusal Grounds: What Each One Now Requires

The eight grounds are unchanged:

The burden of additional costs
An inability to reorganise work among existing staff
An inability to recruit additional staff
A detrimental impact on quality
A detrimental impact on performance
Detrimental effect on ability to meet customer demand
Insufficient work for the periods the employee proposes to work
Planned structural changes to the business

Under the new reasonableness test, for each ground you rely on you must:

Name the specific impact. "It would affect business needs" is not enough. Which customers? Which tasks? What measurable cost or gap?
Explain why that impact makes refusal proportionate. If an employee wants to work from home on Fridays and the only real impact is rescheduling one meeting, a tribunal is unlikely to find refusal reasonable.
Show what alternatives you considered. Trial periods, modified arrangements, phased changes. A refusal that involved no consideration of alternatives looks weak in any hearing.

What a Compliant Refusal Looks Like

Here is how the same refusal reads before and after the ERA 2025 standard.

Old approach (Sarah's letter): "We are unable to accommodate this request due to an inability to reorganise work among existing staff."

New approach: "We have carefully considered your request to adjust your start time from 7am to 9am on Mondays, Wednesdays and Fridays. We cannot accommodate this because it falls under ground 2 (inability to reorganise work among existing staff) and ground 6 (detrimental effect on ability to meet customer demand). Our delivery schedule requires a supervisor sign-off by 8am on all five days. We currently have one qualified supervisor covering this function on your shift. We explored whether another team member could be upskilled to cover the three affected mornings but do not have a trained candidate available within the two-month response period. We also considered a phased start, beginning in January, but the same coverage gap applies. We consider refusal reasonable in these circumstances. You have the right to appeal this decision within 14 days of this letter."

That second response is defensible. The first is not, under Autumn 2026 rules.

When Do the Changes Take Effect?

The ERA 2025 received Royal Assent on 18 December 2025. The government confirmed these provisions for Autumn 2026. The exact commencement date is set by statutory instrument, which had not been published as of September 2026.

The government consultation on improving access to flexible working closed 30 April 2026. The government response and draft regulations are expected before the commencement date.

What you can treat as confirmed:

These changes are arriving. Autumn 2026 means October to December 2026.
The eight grounds are not being removed or extended.
The reasonableness test is the central change.
The Acas Code of Practice on flexible working will be updated ahead of commencement.

If you receive a request today, process it under current rules. If that decision is still outstanding when commencement arrives, apply the new standard from that point. Do not delay decisions artificially.

What Employers Should Do Before Commencement

Audit your policy now

Does your flexible working policy include: the day one right to request, the eight grounds, a mandatory consultation step, written reasoning requirements, and an appeal right? Any gap needs fixing before October. The EmployerKit Audit checks your current policy against ERA 2025 requirements for £49.

Brief line managers -- not just HR

Most requests are handled by line managers, not HR. A manager who sends a vague refusal email could expose the business to a claim that HR then has to defend. Brief them now on what a refusal must contain.

Replace your refusal template

Any template that cites a ground without specific factual reasoning needs replacing before commencement. The template is not the problem. Vague reasoning is.

Make trial periods your default

A trial period demonstrates genuine consideration, generates evidence if it does not work, and signals reasonableness. If you are not already using them as a default step, start now.

Watch for the updated Acas Code

When the updated Code lands, it becomes the benchmark tribunals apply. An employer who departs from the Code without good reason faces an Acas uplift of up to 25% on any compensation awarded. Follow our ERA 2025 employer checklist for updates as they publish.

How This Connects to the Wider ERA 2025 Wave

The flexible working provisions are one of three ERA 2025 changes landing this Autumn, all at roughly the same time:

Guaranteed hours right: workers can request guaranteed hours after a qualifying period. Read the guaranteed hours guide.
Fire and rehire restrictions: significantly tightened from Autumn 2026. See what is changing.
Flexible working strengthened default: this article.

For the full picture, see our ERA 2025 employer guide.

One more connection worth flagging: the unfair dismissal qualifying period drops from two years to six months on 1 January 2027, set by SI 2026/559. That means from January, an employee with six months' service who resigns after a badly handled flexible working refusal could bring a constructive dismissal claim. The ERA 2025 changes compound each other.

Flexible Working Policy: The Checklist

Before Autumn 2026, confirm your flexible working process covers each of these:

Step	Action required
Receiving a request	Acknowledge in writing; start two-month clock
Initial assessment	Review against role, not blanket policy
Consultation meeting	Required before refusing; explore alternatives
Decision	Written; must cite ground, factual basis, alternatives considered
Reasonableness	Documented assessment, proportionate to the impact
Appeal	Employee right to appeal; timeframe specified in policy
Record keeping	Full file: request, assessment notes, meeting record, decision letter

Frequently Asked Questions

Q: Is flexible working becoming automatic for all employees in 2026?

A: No. Every employee already has the day one right to request flexible working since April 2024. What changes this Autumn is that employers must demonstrate any refusal is reasonable. It strengthens the existing right; it does not create an automatic entitlement.

Q: Can I still refuse a flexible working request under the ERA 2025 rules?

A: Yes. The eight grounds remain unchanged. What changes is the standard you must meet: name the ground, state the specific factual basis, show you considered alternatives, and explain why refusal is reasonable. A well-documented refusal on genuine business grounds will still be lawful.

Q: When exactly do the new flexible working rules come into force?

A: The ERA 2025 confirmed Autumn 2026. The exact date is set by statutory instrument, not yet published as of September 2026. Treat October 2026 as your planning deadline.

Q: I have a flexible working request sitting on my desk right now. Should I wait for the new rules?

A: Process it under current rules. If the decision is outstanding when commencement arrives, apply the new standard from that point. Do not artificially delay the decision.

Q: Do I need to update my flexible working policy before Autumn?

A: Yes. Your managers need to understand the new process before they handle the next request. The gap between current practice and the new standard is wide enough that preparation takes time.

Q: What happens if I refuse without proper reasoning under the new rules?

A: Under current rules, mishandling a request costs up to eight weeks' pay (around £5,600). Where a poorly reasoned refusal also involves indirect discrimination, compensation is uncapped. From January 2027, with the shorter unfair dismissal qualifying period, more employees can bring constructive dismissal claims where a refusal pushes them to resign.

Q: Does this apply to small employers?

A: Yes. No size exemption. A tribunal will consider business size when assessing reasonableness, but the obligation to document and justify refusals applies to every employer.

Update Your Process Before Autumn 2026

The ERA 2025 flexible working changes are not cosmetic. The reasonableness test, written reasoning requirements, and the alternative-consideration obligation represent a genuine increase in what employers must do. Sarah in Leeds revised her letter. The version her manager was about to send would have cost the company far more than the school run hours ever would.

Check your current policy against the new requirements with the EmployerKit Audit for £49, before the changes land.

Sources

This guide is general information for UK employers, not legal advice. Employment law changes and individual circumstances vary. For decisions on specific situations, take advice from a qualified employment law professional.