~120,000
Registered engineers in the UK
2009
Year Gas Safe replaced CORGI
~250,000
Illegal gas jobs per year (estimate)
£0
Cost of checking an engineer
Figures from the Gas Safe Register and HSE, May 2026.
Most UK households assume the engineer at the door is qualified because someone, a friend, a comparison site, a Facebook group, said so. That assumption is the single most expensive shortcut you can take with a gas appliance.
About a quarter of a million gas jobs are still done illegally in the UK every year. Not by villains in vans, mostly by ordinary tradespeople who either let their registration lapse, or who only hold the qualification for one fuel type (LPG) but quietly work on another (mains). The customer almost never knows.
The fix takes about 60 seconds and costs nothing. The verifier widget below walks you through it. The rest of this guide explains what is on the ID card, what each qualification actually licenses, and why illegal work voids your insurance, your warranty and, in the worst cases, your safety.
Check the engineer at your door in four ticks
Tick what you can confirm. We tell you live whether to let them work or step back.
Verification logic verified May 2026. The only authoritative source is the Gas Safe Register itself, this widget points you straight at it.
Where standard advice fails
Why most Gas Safe articles only tell you half the story
Standard UK guides tell you to "ask for the Gas Safe ID card". That is correct and it is not enough. A real check has four steps, not one.
The card is a piece of plastic. It tells you who registered, when the card was issued, and which categories the engineer can legally work on. None of that proves the registration is still live today. Registrations lapse. Engineers get struck off. Cards get borrowed. The card and the live register are two different things, and only one of them is the legal source of truth.
The bigger gap is the qualification line on the back of the card. Most articles do not explain it, so most customers do not read it. A "Gas Safe engineer" with only the cooker qualification (CKR1) is not legally allowed to touch a boiler, and an LPG-only engineer cannot work on mains natural gas. Those distinctions are written on the back of every card. They are also the reason "registered but illegal" is a real category in the UK.
The verifier above forces you through all four checks: card present, name matches, card in date, qualification covers the job. That is what a real check looks like. Anything less is faith, not verification.
Read the card properly
What is actually printed on a Gas Safe ID card
Every card carries the same information in the same places. The front identifies the engineer; the back tells you what gas work they can legally do.
Front of the card
-
1
Engineer name
Must match the person standing in front of you. Different name = different engineer = wrong card.
-
2
Company name
The registered business. Sole traders register under their own name.
-
3
Gas Safe registration number (7 digits)
Identifies the business. Look it up at gassaferegister.co.uk.
-
4
Licence number (5 to 7 digits, starts with a letter)
Identifies the individual engineer.
-
5
Expiry date
Cards are renewed annually. An expired card means an expired right to work on your gas.
-
6
Security hologram + QR code
Cards issued from 2018 carry a hologram and a QR code that links to the live entry.
Back of the card
-
1
Domestic / commercial qualifications
Look for "domestic" for any home work.
-
2
Appliance categories the engineer can legally touch
Common categories: boilers (CCN1, CENWAT), cookers (CKR1), fires (HTR1), water heaters (WAT1), meters (MET1).
-
3
Fuel type
Natural gas (mains) vs LPG (cylinder or tank). LPG-only engineers cannot work on mains gas.
-
4
Expiry of each qualification
Each category has its own renewal, usually every five years.
Insider insight
Why "Gas Safe registered" is not always "Gas Safe authorised for your job"
The detail that almost no consumer guide explains is on the back of the card: category codes. Gas Safe registration is not a single licence, it is a stack of per-appliance, per-fuel qualifications. Each one is renewed separately.
A perfectly honest engineer can be on the register but not qualified for your appliance. Cooker installers do not necessarily hold CCN1 + CENWAT for combi boilers. LPG specialists do not automatically hold the mains-gas certification. The card lists the categories the engineer is authorised for, and only those. Anything outside that list is illegal gas work, even if the engineer is registered.
CCN1
Core Domestic Gas Safety, the universal starting point. Must be held by every domestic gas engineer.
CENWAT
Central heating boilers + water heaters running on natural gas. The category for boiler work.
CKR1 / HTR1 / WAT1
Cooker, fire / heater, and dedicated water heater categories. Each is separate.
MET1
Meter installation, needed for any meter swap, including when fitting a smart meter on a gas supply.
The real cost of an illegal job
What happens if you let unregistered gas work go ahead
The £100 you save on the quote disappears the moment one of these triggers.
Your home insurance can be voided
A claim from a fire, explosion or carbon monoxide incident can be refused if the gas work was illegal, and most policies treat unregistered work as illegal.
Your manufacturer warranty is voided
Worcester Bosch, Vaillant, Ideal and Baxi warranties all require Gas Safe work. The warranty dies the moment a non-registered person touches the boiler.
You may struggle to sell or let the property
Conveyancing solicitors and letting agents now ask for the most recent Gas Safe paperwork. No paperwork = price chip or delayed sale.
You bear the safety risk
About 50 deaths a year in the UK are linked to carbon monoxide poisoning. The register exists because gas done wrong is lethal, not because the paperwork is fun.
For trade readers
How to become Gas Safe registered in the UK
Becoming registered is a two-step process: get the qualifications, then apply to the register. The register itself is not a training body.
Step 1
1. Get a recognised qualification
NVQ/SVQ for new entrants (1 to 4 years via apprenticeship or college). ACS (Accredited Certification Scheme) for experienced engineers, typically 4 to 6 weeks of accelerated training plus assessments.
Step 2
2. Hold CCN1 + relevant appliance codes
CCN1 is the core domestic ticket. Add CENWAT for boilers, CKR1 for cookers, HTR1 for fires, WAT1 for dedicated water heaters. Each must be re-certified every 5 years.
Step 3
3. Apply to Gas Safe Register
Application around £190 + VAT, plus per-engineer fees. Annual renewal ~£140 to £160 + VAT. First three months are a probation period with extra reporting.
Direct contact
Reach the Gas Safe Register directly
Report illegal gas work
Reports can be made anonymously and are investigated by the HSE.
Email [email protected] · Address: Gas Safe Register, PO Box 6804, Basingstoke RG24 4NB.
Gas Safe Register FAQ
Gas Safe Register questions, answered
Go to the live register at gassaferegister.co.uk. Search by the engineer's licence number, registration number, business name or postcode. Each result tells you which appliances and fuel types the engineer is legally allowed to work on. Bookmark the page, it is the only official source.
No. Gas Safe replaced CORGI on 1 April 2009 in Great Britain and on 1 April 2010 in Northern Ireland. CORGI was a trade-association scheme; Gas Safe is the statutory register run on behalf of the Health and Safety Executive (HSE). If someone still talks about being "CORGI registered", treat that as a red flag, the scheme has not existed for over 15 years.
Do not let them touch a gas appliance. Carrying the ID card is a condition of registration. No card means either the registration has lapsed or the person was never on the register in the first place. Politely cancel and contact the Gas Safe Register on 0800 406 5500.
Only if they work on gas. A plumber who only touches water pipework does not need Gas Safe registration. The moment they connect, disconnect, repair or service any gas appliance, including a boiler, hob, fire or meter, they must legally be on the register for that specific category.
Initial business application is in the region of £190 + VAT, plus a per-engineer fee. Annual renewal runs roughly £140 to £160 + VAT per engineer. Before any of that, the engineer needs a recognised qualification: NVQ/SVQ for new entrants, ACS (Accredited Certification Scheme) for experienced engineers. The core domestic ticket is CCN1, which must be re-certified every five years.
Report it to the Gas Safe Register on 0800 408 5500 (illegal gas work line) or via the form on gassaferegister.co.uk. The register investigates and can prosecute through the HSE. Reports can be anonymous.