Every year in the UK, unregistered fitters install gas appliances they are not qualified to touch. Some of those installations end in leaks, carbon monoxide incidents and worse. The Gas Safe Register itself investigates hundreds of illegal gas work reports every year, and the honest, uncomfortable truth is that many customers only find out afterwards. Verifying your engineer takes two minutes and could save your life. Here is exactly how to do it.
Quick answer
To verify a Gas Safe engineer, ask to see their ID card, check the licence number and photo, confirm the appliance categories listed on the back cover the job you have booked, and cross-check the number at gassaferegister.co.uk or by phone on 0800 408 5500. If any step fails – missing card, expired date, wrong category, evasive answers – do not let the work go ahead.
Why registration matters
Gas Safe Register replaced CORGI in 2009 and is the only official register of legal gas engineers in Great Britain (Northern Ireland has a separate scheme). Working on gas without registration is a criminal offence under the Gas Safety (Installation and Use) Regulations 1998. The register exists because gas mistakes are not merely inconvenient – they cause fires, explosions and carbon monoxide poisoning.
Every registered engineer carries a photo ID card with a unique licence number, the business they work for, and a list of the gas appliance categories they are qualified to work on. Categories matter: an engineer qualified for boilers is not necessarily qualified for cookers, and vice versa. An engineer working outside their categories is working illegally even if they are on the register.
The ID card check
When the engineer arrives, ask for the card before the tools come out. A competent professional expects this and welcomes it. On the front, check:
- The photo matches the person standing in front of you
- The name is legible
- The card expiry date is in the future
- The Gas Safe hologram is present on the front
- The unique 7-digit licence number is clearly printed
Turn the card over. The back lists the categories the engineer is qualified for. For your job you want to see the relevant category listed:
- Cookers: for gas hobs, ovens and range cookers (this is the category you need for cooker installation)
- Central heating: for boilers and radiators
- LPG: separate qualification, needed for bottled gas in narrowboats, mobile homes and off-grid properties
- Commercial catering: for restaurant-grade appliances
- Meters: for meter changes and moves
Read also: Gas cooker installation UK guide
Cross-checking the licence number
The card can be faked. The register cannot. Two quick ways to check:
- Visit gassaferegister.co.uk and enter the licence number in the “Check an engineer” tool.
- Phone Gas Safe on 0800 408 5500. Have the licence number ready.
The results should match the person and business on the card – name, photo, business name and current qualification list. If anything is off – wrong photo, wrong name, expired card, missing category – stop the job. A genuine engineer will not be offended. In fact, most welcome the check because it protects them too.
Read also: Carbon monoxide from gas cookers: signs and prevention
Warning signs to walk away from
Certain behaviours should end the appointment on the spot:
- No ID card at all, or a “sorry, left it at home” excuse
- Card without a hologram or a licence number
- Refusal to let you check the number online
- Cash-only demands to avoid paperwork or VAT
- No willingness to leave a Building Regulations Compliance Certificate
- Pressure to “not bother” with a Gas Safety Record for a landlord property
- Quotes dramatically below the market rate – qualified engineers do not underprice by 50 percent
Report suspected illegal work to Gas Safe Register. They investigate and, where the risk is serious, arrange a free safety inspection of the appliance.
Read also: Landlord’s kitchen safety checklist (UK 2026)
Paperwork after the job
Verifying at the door is step one. Verifying after the work is done is step two. A legally-installed gas cooker must come with:
- Building Regulations Compliance Certificate – proof the work meets Part J of the Building Regulations, submitted to your local authority by the engineer
- Gas Safety Record – if you are a landlord, this is your annual CP12 covering every gas appliance in the property
- An itemised invoice – showing parts, labour, engineer name and Gas Safe number
- Manufacturer paperwork – kept with the appliance for the warranty period
Keep the whole bundle. It is proof for insurance, deposit disputes and future engineers.
If you suspect illegal work
If you think you have already had illegal gas work done in your home:
- Stop using the appliance and, if you smell gas, ring the emergency line on 0800 111 999.
- Report it to Gas Safe Register through the “Report unsafe gas work” form online.
- Request the free investigation and inspection.
- Keep any correspondence, receipts or contact details for the person who did the work.
- Have the appliance re-inspected and, if necessary, re-installed by a genuine Gas Safe engineer before further use.
Conclusion
Verifying a Gas Safe engineer is the cheapest insurance policy in your kitchen. Two minutes of checking beats a lifetime of consequences. When you are ready to book a legal, properly credentialed fitter, use our gas cooker installation service in London – every technician arrives with current ID and the correct category on the card.
