To check a Gas Safe engineer before you book, ask for their seven-digit licence number (it's on the front of their Gas Safe ID card), then look them up on the Gas Safe Register website or call the Register on 0800 408 5500. Make sure the business name matches the company you're booking, the licence is in date, and the back of the card lists the exact type of work you need, such as "Gas Boiler" for a boiler service. If they can't or won't show you a valid card, don't let them touch your gas. It takes a couple of minutes.
What Gas Safe registration actually means
Gas Safe Register is the official list of businesses that are legally allowed to do gas work. Under regulation 3 of the Gas Safety (Installation and Use) Regulations 1998, anyone working on gas fittings must be competent, and businesses and self-employed engineers doing that work must belong to a class of persons approved by the Health and Safety Executive. In practice, that means being on Gas Safe Register.
The HSE puts it plainly: anyone employed to work on gas appliances in domestic premises must be a Gas Safe registered engineer and competent in that area of gas work. Gas Safe Register says the same rule applies across the UK, the Isle of Man, Guernsey and Jersey.
Two things often catch people out:
- Registration is per business, and each engineer has their own card. According to Gas Safe Register's FAQs, each business gets a registration number, and each engineer working for it gets their own ID card with a licence number. A new card is issued every year, and the licence number changes each time.
- Registered doesn't mean qualified for everything. Engineers are qualified for specific kinds of work: boilers, cookers, fires, water heaters and so on, natural gas or LPG, domestic or commercial. Someone qualified to fit a cooker isn't automatically qualified to install your boiler.
How to read the Gas Safe ID card
Every registered engineer should carry their Gas Safe ID card while they're working. They might show it to you without being asked, or have it on display. If not, ask. A genuine engineer won't mind. Gas Safe Register's guide to the ID card says to check both sides.
The front of the card
- Security hologram: official cards carry a hologram with the Gas Safe logo.
- Licence number: the engineer's unique number, printed at the top and embossed across the middle.
- Start and expiry dates: engineers renew every 12 months, so check the card is current. If it has expired, contact Gas Safe Register.
- The business they work for: it should match the company you contacted.
- Photo: make sure the person at your door is the person on the card.
The back of the card
The back lists the work the engineer is qualified to do, split into domestic and non-domestic, with an expiry date for each. Check that the work you need is listed and still in date. If they're there to service your boiler, for example, Gas Safe Register says the card should list "Gas Boiler". If your home runs on LPG, check the qualification covers LPG as well as natural gas.
Check the engineer and the business on the Gas Safe Register
The card alone won't tell you whether the registration is live today, so do the online check too, ideally before the visit.
- Ask for the licence number when you book. Gas Safe Register says an engineer should be able to show you their card or tell you the number over the phone.
- Search the register. On the Gas Safe Register find and check page you can check an engineer or business by business name, registration number, business phone number, engineer name or licence number.
- Compare the details. The engineer should be listed against the business you're booking, and the qualifications shown should cover your job. The HSE notes that the Register's check service shows engineers' photos and qualification details.
- If in doubt, phone. Gas Safe Register's team can help on 0800 408 5500, or by email at register@gassaferegister.co.uk.
If you haven't chosen anyone yet, the same page lets you search for registered businesses near you by postcode. Whichever website you found an engineer on, including TradesAround, run this check yourself before you book.
What to do if someone isn't registered, or the work looks unsafe
If they can't show a valid card
Gas Safe Register's advice is clear: if an engineer doesn't have a valid Gas Safe ID card or refuses to show you one, don't let them carry out the work, and let the Register know.
Reporting illegal gas work
If you think someone is doing gas work without being registered, Gas Safe Register asks you to gather what you can (names, dates and the address where the work was done) and report it using its online form or by calling 0800 408 5500. The Register investigates and passes what it finds to the authority that can prosecute.
Problems with a registered engineer's work
If a registered business has done work you're not happy with on safety grounds, Gas Safe Register advises going back to the business first and asking them to put it right. If they don't respond, you can raise a gas work concern. The Register can inspect the work and, where it falls below standard, issue a defect notice. It can't help with contractual or money disputes, though.
If you smell gas or think an appliance is unsafe
The HSE says it's illegal to use a gas appliance you suspect is unsafe. Turn it off and leave it until a Gas Safe registered engineer has checked it. If you suspect a leak:
- call the National Gas Emergency number on 0800 111 999
- open doors and windows
- turn off the gas at the meter control valve, if you know where it is
If an engineer labels an appliance "Danger Do Not Use", follow that advice. If you doubt it, the HSE says to follow it in the meantime and ask Gas Safe Register.
Know the signs of carbon monoxide
Carbon monoxide (CO) is one of the main reasons gas work needs doing properly. The HSE describes it as a colourless, odourless, tasteless poisonous gas that is produced when fuel doesn't burn properly, and says around 7 people a year die from CO poisoning caused by gas appliances and flues that haven't been properly installed or maintained or are poorly ventilated.
Warning signs on or around an appliance, according to the HSE:
- yellow or orange flames instead of blue (except fuel-effect fires or flueless appliances designed to burn that colour)
- soot or yellow or brown staining on or around the appliance
- pilot lights that keep blowing out
- more condensation than usual inside windows
Symptoms of CO poisoning can feel like flu, food poisoning or tiredness: headaches, dizziness, breathlessness, nausea, tiredness, chest or stomach pains, erratic behaviour, visual problems and loss of consciousness. If you think your appliance is leaking CO, the HSE says to call 0800 111 999, switch off the appliance, turn off the gas at the meter, open doors and windows, and get urgent medical advice.
The HSE strongly recommends a CO alarm that meets British Standard EN 50291 as a useful early warning, but stresses that an alarm is not a replacement for regular servicing and safety checks by a Gas Safe registered engineer. It advises having gas appliances, flues and pipework serviced at least once a year.
Gas safety records and landlords
If you own and live in your home, there's no law saying you must have an annual gas safety record, although the HSE strongly advises an annual service. For more on what happens when you sell, see our guide on whether you need a gas safety certificate to sell your house.
Landlords are different. Under the landlord duties explained by the HSE and GOV.UK's guide for renters, a landlord must:
- have gas equipment they provide installed and maintained by a Gas Safe registered engineer
- arrange a gas safety check on each appliance and flue every 12 months, by a Gas Safe registered engineer
- keep the record for 2 years, give existing tenants a copy within 28 days of the check, and give new tenants a copy before they move in
Landlords should run the same card and register checks on whoever does the annual check.
Questions to ask before you book
- What's your Gas Safe business registration number, and what's the licence number of the engineer who'll come out?
- Is the engineer qualified for this specific job (for example, gas boiler, cooker or fire, and LPG if that's what you use)?
- For a new boiler or other gas appliance, how will the installation be certified under building regulations? GOV.UK lists Gas Safe Register as the competent person scheme for gas appliances, so a registered business can self-certify the work.
- Will you leave paperwork showing what you checked or did, and any safety issues you found?
- If you find something unsafe, what happens next, and will you explain it before doing any extra work?
- Can I have a written quote before you start?
Thinking of replacing your boiler? Our guide to what a new boiler costs in Oxfordshire in 2026 covers the costs, so you can go into those conversations prepared.
Frequently asked questions
How do I check if a gas engineer is Gas Safe registered?
Ask for their seven-digit licence number, then search for it on the Gas Safe Register website or call 0800 408 5500. You can also search by business name or registration number. Check that the business matches the company you booked and the qualifications cover your job.
Is it illegal to use a gas engineer who isn't Gas Safe registered?
The law sits with whoever does the work. Under the Gas Safety (Installation and Use) Regulations 1998, businesses and self-employed engineers doing gas work must be on the approved register, which is Gas Safe Register. If someone isn't registered, don't let them work on your gas, and report them to Gas Safe Register.
Can any Gas Safe engineer work on any gas appliance?
No. Gas Safe Register says engineers are qualified for specific kinds of work, listed on the back of their ID card. Check the card or the online register shows the work you need, and that it hasn't expired.
Does a homeowner need a gas safety certificate every year?
Not by law, unless you're a landlord. The HSE does strongly advise having gas appliances, flues and pipework serviced at least once a year by a Gas Safe registered engineer.
What does the TradesAround Trust Score cover?
The TradesAround Trust Score is an automated assessment of a business's Google reviews, its Companies House record and its TrustMark registration, and nothing more. Trust Scores aren't for sale. Pro members are listed first, with a Pro badge. It doesn't cover Gas Safe registration, so check the Gas Safe Register yourself before you book.
Find a gas engineer in Oxfordshire
Ready to book? Browse gas engineers in Oxfordshire or heating engineers across Oxfordshire on TradesAround (or heating engineers in Witney if you're in West Oxfordshire). Compare a few, then check the business and engineer on the Gas Safe Register before anyone starts work.
