Yes, in the UK, plumbers who work on gas appliances and systems are required to be registered with Gas Safe. Gas Safe is the official list of gas engineers who are qualified to work safely and legally on boilers, cookers, fires and all other gas appliances.
Plumbers who are not registered with Gas Safe are not legally allowed to work on gas appliances, and it’s also illegal for anyone to use an engineer who is not on the Gas Safe Register. It’s important to check that a plumber is Gas Safe registered before allowing them to work on your gas appliances. You can check the registration status of a plumber by visiting the Gas Safe website and searching for their registration number, or by asking to see their Gas Safe ID card.
It’s important to note that plumbers who are not Gas Safe registered are not necessarily unqualified, they might be specialized in other areas such as drainage, or heating and cooling, and not have the qualifications to work on gas appliances.