An investigation by consumer watchdog Which? found engineers were failing to run basic checks on faulty gas boilers, potentially exposing households to risks of leaks and explosions, The Mirror has reported.
Out of 10 qualified engineers, eight had failed to do one or more of the minimum legal checks on central heating boilers.
Six in 10 did not spot that the operating pressure had been set too high, which could result in overheating.
Two engineers out of the 10 failed to take the case off the boiler to check the seal.
Hidden cameras filmed the workmen and experts assessed each boiler service against gas regulations and the manufacturer’s servicing instructions.
Only two met the legal requirements, according to the undercover investigation, but none followed the instructions properly.
Which? has passed its file to the Gas Safe Register.