Allegations that scores of fire safety lapses could trigger a serious accident at the Hunterston B nuclear power station in North Ayrshire are under investigation by the UK Government's nuclear safety watchdog, the Sunday Herald can reveal.

The station's former fire safety officer, Maxwell Lyall, has warned that numerous flaws in fire doors, seals and other critical safety measures could lead to loss of life and leaking radioactivity in the event of a fire. He has accused contractors of cutting corners and putting public safety at risk.

Lyall has been backed by his local SNP MSP, the Scottish Education Minister Michael Russell, who is demanding urgent action. "I take his accusations very seriously," Russell said. "If they are correct and are confirmed, Hunterston would have to be closed immediately. We need to know as quickly as possible whether they are true."

Russell has met Lyall and taken up his allegations with the Scottish and UK governments. "There needs to be a thorough investigation," he told the Sunday Herald. "The UK government is not showing sufficient urgency."

The Office for Nuclear Regulation (ONR) said its inspectors were examining his allegations.

Lyall worked as the fire protection engineer at Hunterston for 10 years, employed by the site's main contractors, Balfour Beatty. He has had 30 years' experience assessing fire safety at a wide range of locations including the government intelligence agency, GCHQ, in Cheltenham and the London underground.

He has listed numerous alleged failings at Hunterston, including flaws in up to 100 fire seals, some of them around the reactor pile cap. Fire doors have been painted with more than 20 coats of inflammable gloss paint instead of a fire-resistant paint, he said, and have gaps underneath them and plastic coverings that have not been tested for fire risks.

"Any fire in a nuclear power station is very dangerous, and if there's a fire, it will spread throughout the whole building," Lyall said.

"It is my contention that Balfour Beatty has cut corners and papered over the cracks despite my best efforts to persuade them otherwise," he added. "They know I'm correct."

Lyall, aged 60, was dismissed for gross misconduct in December last year and lives in Rothesay on the Isle of Bute. He said that he was sacked after he lost his temper with his manager because his complaints about safety were being ignored.

He had never faced any disciplinary action before that, he said, and was adamant that he did not bear any grudges. "It's not about reprisal, it's because it's not safe," he insisted.

Rita Holmes, who represents Fairlie Community Council on the stakeholder group, welcomed the investigations by nuclear inspectors. "If Mr Lyall's claims are proved to have substance, let's hope they are not just the tip of the iceberg," she said.

The Office for Nuclear Regulation said fire safety inspectors had visited Hunterston after Lyall's allegations had been raised by Russell. Although they concluded that regulatory requirements were being met, "some areas to enhance safety were identified", said an ONR spokesman.

"Health and safety and specialist ONR inspectors are continuing to review some of the specific elements of Mr Lyall's allegations as part of our routine regulatory activities, with the next planned inspection on fire safety at Hunterston B being scheduled for September."

Balfour Beatty declined to comment, but EDF Energy, the French company that runs Hunterston B, pointed out that ONR had the power to close down operations if necessary. "We take all such concerns seriously, whether it is raised by a member of staff, the public or a contractor, and fully investigate these. In this case, we have completed a rigorous investigation of all fire systems highlighted by this individual and found nothing of concern," said a company spokeswoman.