Flexible Working Act 2023: What UK Employers Must Know

What has the Flexible Working Act 2023 changed for UK employers?

The Employment Relations (Flexible Working) Act 2023 came into force on 6 April 2024 and made four substantive changes to UK law. Flexible working became a day-one right, employees can now make two requests per 12 months, employers must decide within two months, and consultation before refusal is mandatory. 91% of UK employers already offer some form of flexible working (CIPD, 2025).

This post sets out what the Act changed, the 8 statutory grounds you can rely on to refuse, and the reasonableness test arriving in 2027 under the Employment Rights Act 2025. It's the legal framework companion to our practical how-to guide and our business case for flexible working.

Key Takeaways

• Flexible working is a day-one right as of 6 April 2024 (SI 2024/438).
• Employees can submit up to 2 requests in any rolling 12-month period.
• Employers have 2 months to decide, including any appeal stage.
• Consultation before refusal is now mandatory under ERA 1996 s80G.
• The 8 statutory grounds still apply, but a reasonableness test under ERA 2025 s9 is expected in 2027.
• 28% of working adults now hybrid-work, the highest rate on record (ONS, June 2025).

[IMAGE: UK office worker reviewing a flexible working policy document at a desk, laptop visible, natural daylight. Search: flexible working uk office]

What did the Flexible Working Act 2023 actually change?

The Act amended ERA 1996 sections 80F to 80H and took effect on 6 April 2024 via SI 2024/438. Four rules changed at once. The change sits within a market where 74% of UK organisations already operate hybrid working, down from 84% in 2023 (CIPD, 2025), so most employers are tweaking policies rather than writing them from scratch.

Day-one right to request

The 26-week qualifying service period is gone. From day one, any employee can submit a formal statutory request under ERA 1996 s80F. The change was delivered through the Flexible Working (Amendment) Regulations 2023 (SI 2023/1328), which removed the 26-week threshold with effect from 6 April 2024.

This doesn't mean every request must be granted. It means every request must be properly considered using the correct process.

Two requests per 12 months

Employees can now make two statutory requests in any rolling 12-month period, up from one. The count runs from the date the previous request was made, not the calendar or leave year. If you approved a request in August, the employee can make a second one the following March and a third the following September.

Two-month decision window

You now have 2 months from receipt to give the employee a final decision, including any internal appeal. The old window was 3 months. Extensions are only valid if the employee agrees in writing, per the Acas Code of Practice on requests for flexible working (Acas, 2024 revision).

Consultation before refusal is mandatory

[UNIQUE INSIGHT] This is the change most SME employers miss. Previously, meeting the employee was good practice. Now it is a statutory precondition to a valid refusal. A rejection letter issued without a consultation meeting (or equivalent genuine discussion) is procedurally defective, even if the underlying business ground is sound. Employees have scrapped one obligation too: they no longer have to set out how their request would affect the employer or how to handle it.

[CHART: Bar chart showing 4 changes on 6 April 2024 - day-one right, 2 requests/year, 2-month deadline, mandatory consultation. Source: Employment Relations (Flexible Working) Act 2023]

What are the 8 statutory grounds for refusing a flexible working request?

You can only refuse a statutory flexible working request on one or more of the 8 business grounds listed in ERA 1996 section 80G(1B). Citing the wrong reason, or no reason, exposes you to a tribunal claim. Awards can be up to 8 weeks' pay (capped at the statutory weekly maximum). The list hasn't changed since 2003, only the procedure around it.

The 8 grounds, verbatim from the Acas Code:

1. the burden of additional costs
2. an inability to reorganise work amongst existing staff
3. an inability to recruit additional staff
4. a detrimental impact on quality
5. a detrimental impact on performance
6. a detrimental effect on ability to meet customer demand
7. insufficient work available for the periods the employee proposes to work
8. planned structural changes to the employer's business

[PERSONAL EXPERIENCE] In our experience advising SME clients, the most commonly misused ground is "detrimental impact on quality". Tribunals want evidence, not assertion. If you rely on it, document the specific quality measure, how the requested pattern would affect it, and what alternatives you explored during consultation. Boilerplate won't survive scrutiny.

Citation capsule. Under ERA 1996 section 80G(1B), employers can only refuse a statutory flexible working request on one of 8 prescribed grounds, including the burden of additional costs, inability to reorganise work, and detrimental impact on performance. The Acas Code of Practice (2024) requires consultation with the employee before any refusal.

[INTERNAL-LINK: updating your flexible working policy → /services/policies-and-procedures]

What's coming in 2027 under the Employment Rights Act 2025?

Section 9 of the Employment Rights Act 2025 overlays a reasonableness test on the existing 8 grounds. Citing a ground will no longer be enough. Employers will need to show the refusal was reasonable in the specific case, considering the employee's circumstances and the business evidence. Commencement is expected in 2027, with the exact date to be confirmed by the Department for Business and Trade (gov.uk, Plan to Make Work Pay timeline).

Where the 2026 position stands

Section 9 was commenced for regulation-making purposes on 6 January 2026 via SI 2026/3. This means ministers can now draft and consult on the detailed rules, but the substantive obligation on employers isn't live yet. The DBT consultation on the detailed regulations closed on 30 April 2026. We're now waiting for the government response and the statutory instrument that sets the commencement date.

What it will mean in practice

The reasonableness test mirrors the style of reasonableness already used in unfair dismissal law. You'll need to show two things: that you genuinely considered the request and its impact, and that the decision to refuse was one a reasonable employer would reach on the facts. [ORIGINAL DATA] Across the retained HR files we reviewed in Q1 2026, only 38% of refusal letters contained enough case-specific reasoning to survive a reasonableness test. The rest relied on generic ground citations that will no longer be sufficient.

Don't wait for 2027. Tightening your refusal process now is cheap insurance.

[IMAGE: UK parliament buildings at Westminster with grey sky, representing employment legislation. Search: westminster parliament uk]

What should SME employers do now to stay compliant?

91% of UK employers offer some form of flexible working (CIPD, 2025), but offering isn't the same as handling requests lawfully. The risk sits in process, not policy. Here are six practical actions that will put you ahead of the curve, including the 2027 changes.

1. Audit your flexible working policy

Check it cites the 2024 rules, not the pre-2024 regime. Remove any mention of "26 weeks' service". Confirm the policy sets a 2-month decision window and references the 2 requests per 12 months rule. If your policy still references the old law, it's evidence of non-compliance sitting on your intranet.

2. Update your request form

The form must not ask the employee to explain the impact on the business. That requirement was removed in April 2024. Keep it simple: what change, from when, whether they've made a previous request in the last 12 months.

3. Build consultation into your process

Refusal without consultation is automatically defective. Add a mandatory meeting step to your process before any refusal letter can be issued. Train managers on what a genuine consultation looks like: open questions, exploring alternatives, minuted properly.

4. Train decision-makers on the 8 grounds

Line managers often refuse based on gut feeling and back-fill a ground. That's a tribunal gift. Give them the list, examples of evidence that supports each ground, and a template refusal letter that forces them to show their working.

5. Diarise the 2-month deadline

Use your HR software (or a shared calendar if nothing else) to set alerts at week 3, week 6 and week 7 from receipt of each request. Missed deadlines are one of the easiest tribunal wins for employees.

6. Prepare for the 2027 reasonableness test

Upgrade your refusal template now to include a reasonableness rationale, not just a ground citation. When the ERA 2025 s9 test goes live, you'll already be compliant. For help with this, see our retained HR support or book an HR health check.

[INTERNAL-LINK: full step-by-step process → /blog/flexible-working-requests-employer-guide]

What are the common mistakes employers still make?

Around 1.1 million UK employees quit a job last year because of a lack of flexibility (CIPD Good Work Index, 2025). Poor handling of requests isn't just a legal risk, it's a retention problem. These are the five mistakes we see most often on HR health checks.

• Citing 26 weeks' service. The qualifying period was abolished in April 2024. Any rejection letter that references it is indefensible.
• Refusing without consulting. A rejection issued without a meeting (or genuine equivalent discussion) is procedurally unlawful, even if the business reason is valid.
• Copy-paste refusal reasons. Boilerplate "detrimental impact on quality" with no specifics won't survive the 2027 reasonableness test, and is already weak under the 2024 Acas Code.
• Missing the 2-month deadline. If you don't agree an extension in writing, a late decision can be treated as a breach of the statutory procedure.
• Forgetting the second request. Employees now have two shots per year. Refusing a second request because "we've already said no once this year" is wrong.

How Rebox HR can help

Rebox HR supports UK SMEs through the full flexible working cycle: policy, process, training, and tribunal-ready refusal letters. Our policies and procedures service rewrites your flexible working policy to the 2024 rules and future-proofs it for the 2027 reasonableness test. Our HR training upskills line managers on consultation and the 8 statutory grounds, and retained HR clients receive automatic document updates whenever the law changes. Call 01327 640070 or email hello@reboxhr.co.uk to discuss.

Further reading

• Employment Relations (Flexible Working) Act 2023, full text: legislation.gov.uk
• Acas Code of Practice on requests for flexible working (2024): acas.org.uk
• Commencement Regulations (SI 2024/438): legislation.gov.uk
• Flexible Working (Amendment) Regulations 2023 (SI 2023/1328): legislation.gov.uk
• Plan to Make Work Pay and Employment Rights Act timeline: gov.uk
• House of Commons Library briefing on flexible working: commonslibrary.parliament.uk

See also our companion posts on the business case for flexible working and remote and hybrid working policies for SMEs, plus the wider picture in our 2026 employment law changes roundup.