Changes to the Working Week: What Employers and Employees Need to Know.

Four-Day Working Week: Legal Issues for Employers and Employees

The traditional five-day working week is under increasing scrutiny as employers consider new ways to improve productivity, recruitment, retention and work-life balance. Some UK businesses have trialled a four-day week, often with no reduction in pay, while others use compressed hours, hybrid working or flexible start and finish times.

Is There a Legal Right to a Four-Day Week?

There is currently no automatic legal right to work a four-day week in the UK. However, eligible employees have the right to make a statutory flexible working request from the first day of employment. A request may include compressed hours, reduced hours, changed working days, hybrid working or other changes to when, where or how work is done.

An employer must consider a statutory flexible working request reasonably. It can refuse a request only for one or more of the permitted business reasons, such as cost, impact on quality or performance, inability to reorganise work, difficulty recruiting additional staff, or planned structural changes.

Four-Day Week and Compressed Hours

A four-day week can mean different things. In some models, employees work fewer hours for the same pay. In others, employees work the same total hours compressed into four longer days. These are legally and practically different arrangements.

Compressed hours may help employees gain an extra non-working day. Still, longer working days can raise issues around rest breaks, fatigue, childcare, caring responsibilities and health and safety. Employers should be clear about which model is being proposed before making changes.

Lessons from UK Trials

The UK four-day week pilot in 2022 involved 61 companies and around 2,900 workers. The trial reported positive outcomes for many participating employers, including improved wellbeing, reduced burnout, lower staff turnover and broadly maintained business performance.

However, a four-day week will not suit every workplace. The practical impact may depend on the sector, staffing levels, customer demand, shift patterns, workloads, management systems and whether productivity improvements are realistic.

Employment Contract Changes

Employers should not assume that working patterns can be changed informally. A move to a four-day week may require changes to employment contracts, staff handbooks, working time policies, holiday calculations, pay arrangements and performance expectations.

Contract wording should make clear whether the employee's hours are reduced or compressed, whether pay remains the same, what days are worked, how overtime is handled, whether the arrangement is permanent or trial-based, and how it can be reviewed.

Working Time Regulations

Any new working pattern must comply with the Working Time Regulations 1998. Employers should consider the 48-hour average weekly working limit, daily and weekly rest periods, rest breaks, night work rules and holiday entitlement.

Where employees work longer days under a compressed-hours model, employers should check whether the pattern creates fatigue, safety or wellbeing risks. This is particularly important in sectors involving driving, machinery, healthcare, construction, manufacturing, security or safety-critical work.

Holiday Pay and Annual Leave

Holiday entitlement must be calculated carefully when employees move to a four-day pattern. Full-time employees are entitled to 5.6 weeks' paid annual leave, but the number of days or hours may need to be recalculated to reflect the new working pattern.

Employers should also consider bank holidays. If a workplace closes on bank holidays, employees on different shift patterns should not be treated unfairly because their non-working day falls on a Monday or Friday.

Discrimination and Fairness Risks

A four-day week or compressed-hours policy should be applied fairly. Problems can arise when some teams are allowed flexible patterns while others are denied them without a clear business reason.

Employers should also consider potential indirect discrimination risks. For example, rules that disadvantage part-time workers, carers, disabled employees, parents or particular age groups may need objective justification. Requests linked to disability, caring responsibilities, pregnancy, religion or other protected characteristics should be handled carefully.

Performance and Productivity

A four-day week is more likely to work where employers review workloads, meetings, processes, technology and management expectations. Simply compressing five days of work into four days without changing how work is organised may increase stress rather than improve productivity.

Employers considering a trial should set clear objectives, review customer service, monitor workload, check wellbeing and collect feedback from staff and managers. Trial periods should have clear start and end dates and a fair review process.

Flexible Working Requests

Employees who want to move to a four-day week should make a clear flexible working request. The request should explain the proposed pattern, whether the employee is requesting reduced hours or compressed hours, and how they believe the arrangement could work in practice.

Employers should deal with requests promptly and reasonably, discuss alternatives where appropriate, and confirm the decision in writing. If a request is refused, the reason should be clear and linked to one of the recognised business grounds.

When Legal Advice May Be Needed

Employers may need legal advice before introducing a four-day week, changing contracts, running a trial, refusing flexible working requests or applying different working patterns across teams. Advice can help reduce the risk of breach of contract, unlawful deductions from wages, discrimination claims or working time breaches.

Employees may need advice if a flexible working request has been refused unfairly, if working hours have been changed without agreement, or if a new pattern creates pay, holiday, discrimination or health and safety concerns.

Current Position

The four-day week remains a voluntary workplace model rather than a statutory entitlement. Interest in shorter and more flexible working patterns continues, but employers must still comply with employment contracts, flexible working rules, wage law, holiday entitlement, discrimination law and working time protections.

For many businesses, the safest approach is to start with a clear policy or trial, consult staff, record agreed contract changes and review the arrangement before making it permanent.

Disclaimer

Solicitors.com is not a firm of solicitors and does not provide legal advice. The information on this page is for general guidance only and should not be relied upon as a substitute for advice from a regulated solicitor. Employment law and workplace practice can change, and how the law applies will depend on the facts of each case.

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