Paul Irvine, 44, and Frank Dever, 46, from Paisley, were dismantling the staircase at the former Priory House Hotel in Largs.

Their employer, Paisley firm Ossian Construction Ltd was today fined £6,000 at Kilmarnock Sheriff Court after an investigation into the incident which left one of the men seriously injured.

On 17 September 2007 the two workers were removing individual stair treads, weighing between 120 and 150 kg, by breaking them up with sledgehammers when the staircase collapsed. The men fell almost four metres to the basement below and were struck by the falling debris.

Irvine was trapped by pieces of the stone treads so large it needed several men to shift them.

He sustained fractures to every one of his ribs and three vertebrae, suffered a punctured lung, and suffered significant crush injuries to his foot and a finger.

Dever suffered bruising and cuts. The events have had a significant traumatic effect on both men.

Ossian Construction Ltd of Glasgow Road, Paisley, pleaded guilty to safety breaches.

Following the case, HSE inspector Annette Leppla said: “This was a serious and entirely preventable incident that will affect Mr Irvine in particular for the rest of his life.

“Ossian Construction failed in their duty of care to their employees and both Mr Dever and Mr Irvine are lucky to be alive.

“It’s not always obvious how old buildings are put together, and therefore it is particularly important to seek competent advice before any demolition work is undertaken.

“All employers carrying out working at height must make sure they plan this work properly and give their employees the training and supervision they need to do the work safely.”