Permit to Work: The Complete UK Guide to High-Risk Work Authorisation

A permit to work system is one of the most critical safety controls on any construction or industrial site. It exists for one reason: to make sure high-risk activities are properly planned, authorised, and controlled before anyone starts work.

Despite this, permit to work systems are frequently misunderstood. Some sites treat them as permission slips. Others use them as a substitute for proper risk assessments. Neither approach works.

This guide explains what a permit to work actually is under UK law, when you need one, how to set up an effective system, and how permits relate to your RAMS documentation.

What Is a Permit to Work?

A permit to work (PTW) is a formal, documented procedure that authorises certain people to carry out specific work at a specific time, and sets out the precautions required for safe completion.

It is not a risk assessment. It is not a method statement. It is a management control that ensures:

• The work has been properly planned and risk assessed
• The necessary precautions are in place before work starts
• Everyone involved understands the hazards and controls
• There's a clear audit trail of who authorised what, and when

The HSE describes a permit to work as "a formal recorded document used to control work which is identified as potentially hazardous."

When Do You Need a Permit to Work?

Permits to work are required for activities where the risk is significant enough that normal safe systems of work need additional controls. The key principle: the permit doesn't make the work safe — it ensures the safety measures are in place before work begins.

Common activities requiring permits to work:

Hot Works

Any activity involving open flames, grinding, welding, brazing, or other ignition sources. Hot works permits are essential because:

• Fire risk extends beyond the immediate work area
• Combustible materials may be hidden behind walls or floors
• Post-work fire watch is required (typically 60 minutes minimum)

Confined Space Entry

Entering tanks, vessels, sewers, excavations, or any space with limited access where a hazardous atmosphere could develop. Confined space regulations require a safe system of work that almost always includes a permit system.

Working at Height

While not every working at height task needs a formal permit, complex or high-risk height work often does — particularly on fragile roofs, near unprotected edges, or where multiple contractors are working above each other.

Electrical Work

Live working (where unavoidable) and work near high-voltage equipment requires formal electrical permits. The Electricity at Work Regulations 1989 require safe systems of work for all electrical activities.

Excavation and Ground Works

Digging near buried services (gas, electric, water, telecoms) or in contaminated ground. Excavation permits ensure service locations have been confirmed and supports are adequate.

Demolition

Controlled demolition work where structural stability could be affected. Demolition permits ensure the correct sequence is followed and exclusion zones are maintained.

Work on Pressurised Systems

Breaking containment on any pressurised system (steam, compressed air, hydraulic, process fluids) requires formal isolation and permit procedures.

Roof Work

Accessing and working on any roof, particularly flat roofs with concealed fragile areas. Roof work permits ensure access routes, edge protection, and rescue arrangements are in place.

UK Legislation and Permits to Work

No single UK regulation mandates "you must have a permit to work system." Instead, permits are a recognised best practice for meeting duties under several regulations:

Health and Safety at Work etc. Act 1974

Section 2 requires employers to provide safe systems of work. For high-risk activities, a permit to work is the accepted way to demonstrate compliance.

Management of Health and Safety at Work Regulations 1999

Regulation 4 requires employers to implement preventive and protective measures. Permits to work are a key administrative control.

CDM 2015

CDM 2015 requires contractors to plan, manage, and monitor construction work to ensure safety. The construction phase plan should specify which activities require permits.

Confined Spaces Regulations 1997

Regulation 4 requires a safe system of work for confined space entry, which should include a permit system for most confined space work.

Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR)

DSEAR requires controls for work in areas where explosive atmospheres may occur. Permits to work are essential for hot works and similar activities in these zones.

HSE Guidance (HSG250)

The HSE's guidance document HSG250: Guidance on Permit-to-Work Systems is the definitive UK resource. While not law, it represents accepted best practice and is referenced by regulators and courts.

Permit to Work vs RAMS

This is where confusion often arises. Here's how they differ:

Document: Risk assessment — Purpose: Identify hazards and evaluate risks — When Used: For every task

Document: Method statement — Purpose: Step-by-step safe working procedure — When Used: For medium/high risk tasks

Document: RAMS — Purpose: Combined risk assessment + method statement — When Used: Industry standard for task documentation

Document: Permit to work — Purpose: Authorisation that safety measures are in place — When Used: For high-risk activities only

You always need RAMS. You only need permits for high-risk activities.

The correct flow is:

1. RAMS identify the hazards and define the control measures for the task
2. Permit to work verifies those controls are actually in place before work starts
3. The permit references the specific RAMS document
4. Work only begins when both the RAMS and the permit conditions are satisfied

Think of RAMS as "what we need to do to make this safe" and the permit as "confirmation that we've actually done it."

How to Set Up a Permit to Work System

An effective permit to work system has five elements:

1. Permit Request

The contractor or supervisor submits a request specifying:

• What work is planned
• Where and when
• What hazards are involved
• What RAMS are in place
• What isolations or precautions are needed

2. Preparation and Authorisation

The permit issuer (a competent, authorised person — usually the site manager or principal contractor's representative) checks that:

• The risk assessment is adequate
• The method statement is suitable
• Required isolations have been made (energy, mechanical, process)
• The work area is safe to enter
• Required safety equipment is available
• Workers are competent and briefed

Only when satisfied does the issuer sign and date the permit.

3. Issue and Receipt

The permit is issued to the person responsible for the work, who signs to acknowledge:

• They understand the hazards and controls
• They will work within the permit conditions
• They will report any changes or problems

A copy of the signed permit should be displayed at the work location.

4. Monitoring

During the work:

• Conditions should be checked periodically
• Any changes (weather, adjacent work, unexpected hazards) may require the permit to be suspended
• Cross-permits should be checked (e.g., hot works and confined space work in the same area)

5. Handback and Cancellation

When work is complete:

• The work area is left safe (post-work fire watch for hot works, reinstatement for excavations)
• The person in charge hands back the permit
• The permit issuer inspects the area and cancels the permit
• The cancelled permit is filed for audit purposes

Common Permit to Work Mistakes

Using permits as the risk assessment. A permit is not a risk assessment. If the RAMS aren't done properly, the permit is just a rubber stamp on an unsafe job.

Issuing permits for the day/week. Permits should cover specific tasks, not time periods. A "hot works permit for Monday" is meaningless if the work changes location or conditions.

Allowing self-issue. The person doing the work should never issue their own permit. The whole point is independent verification that controls are in place.

Not cancelling permits. Uncancelled permits mean nobody checked whether the work was completed safely. This is especially dangerous for hot works, where post-work fire watches are critical.

Too many permits diluting the system. If everything needs a permit, nothing gets the attention it deserves. Reserve permits for genuinely high-risk activities and use RAMS for everything else.

Not training people on the system. Everyone on site should understand what permits are, why they exist, and what to do if they see work happening without one.

Permit to Work Template: Key Elements

Every permit to work should include:

1. Permit number and type — unique identifier and category (hot works, confined space, etc.)
2. Work description — what is being done, where, and by whom
3. Hazard identification — specific hazards related to this work
4. Precautions checklist — isolations completed, equipment available, area cleared
5. RAMS reference — the specific RAMS document number covering this activity
6. Duration — start time and expiry time (permits should never be open-ended)
7. Authorisation — issuer signature, date, and time
8. Acceptance — recipient signature confirming understanding of conditions
9. Extensions — procedure for extending the permit if work overruns
10. Handback — completion signature with confirmation work area left safe
11. Cancellation — issuer confirmation after inspection

How Permits Fit into the CDM Framework

On a CDM project, the permit to work system is part of the construction phase plan:

• The principal contractor establishes the permit system for the site
• The construction phase plan specifies which activities require permits
• Individual contractors request permits before starting high-risk work
• The principal contractor (or their appointed permit issuer) authorises permits
• All permits are filed as part of the project safety records

This hierarchy ensures consistent safety standards across all contractors on site, regardless of how many different companies are working there.

Digital Permit Systems

Paper-based permit systems have served the industry for decades, but they have limitations:

• Permits can be lost or damaged
• It's hard to check for conflicting permits (hot works and confined space in the same area)
• Audit trails are manual and time-consuming
• Post-work checks can be forgotten

Modern digital systems address these issues with:

• Real-time permit status visible to all site staff
• Automatic conflict checking
• Photo evidence of conditions and isolations
• Automatic reminders for handback and cancellation
• Digital audit trail for compliance records

When combined with AI-generated RAMS, digital permit systems create a fully documented safety management system where every high-risk activity is risk assessed, method stated, and formally authorised before work begins.

Key Takeaways

• A permit to work is an authorisation control, not a risk assessment — you need both
• Use permits for high-risk activities: hot works, confined spaces, height work, electrical, excavation, demolition
• The permit verifies that RAMS controls are actually in place before work starts
• Follow the five-step process: request, authorise, issue, monitor, handback
• Never allow self-issue, open-ended permits, or uncancelled permits
• On CDM projects, the permit system sits within the construction phase plan
• Digital systems and AI RAMS tools can streamline the documentation while maintaining the safety controls