On 12 August 2025, Northolt in London recorded a sweltering 33.4 °C—part of the UK’s fourth heatwave of the summer—prompting an amber heat-health warning across wide swaths of England. The Met Office forecasts that such extremes are becoming the norm, with a 50% chance of another 40 °C day within a dozen years.

Against this backdrop, Deputy Prime Minister Angela Rayner and four other cabinet ministers are now advocating for mandatory maximum workplace temperatures, urging employers to allow extra breaks, flexible hours—or even early finishing—when heat becomes dangerous.

Why This Issue Demands Attention Now

• In just the past month, scientists voiced “profound concern” about the rising frequency and intensity of heatwaves in the UK. Days with temperatures over 5 °C above historical averages have doubled.
• From 1–4 June 2025, researchers from Imperial College London estimate that extreme heat caused approximately 570 heat-related deaths in the UK in just four days.
• Heat’s toll isn’t just deadly—it’s economically crippling. Last year saw 1,311 heat-related deaths, and productivity is already suffering during these blistering spells.

The Current Legal Landscape

As it stands, there is no legal maximum temperature for UK workplaces. The Workplace (Health, Safety and Welfare) Regulations 1992 require employers to maintain a “reasonable” working temperature—but only specify minimum thresholds (16 °C, or 13 °C for strenuous work)—not upper limits.

In absence of maximums, the TUC (Trades Union Congress) is demanding stronger rules:

• Employers must act when indoor temperatures exceed 24 °C and workers feel uncomfortable.
• Work should stop when temperatures hit 30 °C for office-based roles—or 27 °C for strenuous jobs.

But government responses remain cautious. While the Environment Audit Committee warned of heat-related deaths tripling by 2050, ministers say there are “no plans to impose a maximum” yet.

Legal experts warn of a one-size-fits-all trap: high heat could be inherent to certain jobs—like bakeries or foundries—making fixed limits “arbitrary, inflexible, and unworkable.” Instead, they argue for a focus on “thermal comfort”, tailored risk assessments, and adaptive controls.

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Benefits of Maximum Temperature Rules

• Protecting worker health: Rising temperatures increase risks of dehydration, heatstroke, rashes, fainting—and even loss of consciousness. Outdoor workers face higher cancer risk due to UV exposure.
• Boosting productivity and morale: Studies show heat erodes cognitive performance and focus—cooler environments help teams stay sharp.
• Strengthening employer brand: Climate-aware policies resonate with jobseekers increasingly focused on wellbeing and sustainability.
• Future resilience: With projections of more frequent heatwaves, proactive planning is not just sensible—it’s essential.

Counterpoints & Employer Concerns

• Cost and logistics: Installing air conditioning, retrofitting buildings, or adjusting shifts can be expensive—especially for small businesses.
• Grey areas: Indoor vs outdoor work, varying levels of physical exertion, and seasonal peaks complicate standardized rules.
• Enforcement hurdles: Who sets the threshold? Workers? Employers? Regulators? The implementation could be subjective.
• Risk of productivity loss: Some critics warn that mandatory stoppages could hamper output during peak periods.

What Employers Can Do—Even Now

Even without new laws, businesses can lead on heat-safety:

Action	Details
Heatwave Policy	Define triggers—e.g. 24 °C—and response plans.
Flexible Hours	Encourage early starts or late finishes to avoid midday peaks.
Mandatory Hydration & Breaks	Ensure staff take regular cooling-down opportunities.
Dress-Code Relaxation	Allow lightweight, breathable clothing when safe.
Environmental Adjustments	Use fans, blinds, shaded areas, and improved ventilation.
Remote Options	Enable home working when heat spikes.
Outdoor Scheduling	Shift heavy physical tasks to cooler mornings or evenings.
Staff Engagement	Consult employees on what measures work best.

Recruitment & Employer Brand—Seizing the Advantage

Companies offering holistic wellbeing—even heat safety—stand out in recruitment.

• Job ads highlighting heat-resilient workplaces signal care and forward-thinking strategy.
• Internally, employees feel valued when their health is prioritized, especially during crises.
• Case in point: some local councils have shifted bin collections to 5 am to protect manual staff—a small step, big message.

Heatwaves are no longer anomalies—they’re milestones of a changing climate. Whether the UK introduces legal maximum temperatures or not, HR leaders can—and should—act now to safeguard people, productivity, and reputation.

Your people are your greatest asset. Keep them safe. Keep them cool.