A Leatherhead company has been fined after its equipment "failure" was one of the principle causes in the death of a young carpenter.

Matthew Gilbert, 27, suffered fatal multiple injuries on August 3, 2005, after a 6.5 tonne concrete slab he was standing on collapsed at Heathrow Airport's terminal 5.

SGB Services Ltd, of Harsco House, Regent Park, Kingston Road, Leatherhead, admitted two breaches of health and safety regulations at Isleworth Crown Court on Friday, November 6 and was fined £30,000, plus £30,000 costs.

Another man Parminder Singh, 24, an engineer's assistant from Slough, also fell and was badly injured, but survived.

James Ageros, prosecuting, said: "They (SGB) manufactured and supplied heavy-duty Threaded Shoring Adapters, (TSAs) whose failure was one of the principle causes of the collapse."

The TSAs were used to hold the massive slabs in place on the car park roof until concrete was poured in over reinforced steel to secure the structure.

Also prosecuted was Laing O'Rourke Infrastructure, of Paramount House, Maylands Avenue, Hemel Hempstead, which admitted one health and safety breach and was fined £75,000, plus £75,000 costs.

The court heard SGB had supplied a sub-standard batch of TSAs in 2003, having failed to ensure they were capable of carrying maximum loads.

Laing O'Rourke failed to have the necessary quality control checks in place to ensure the TSAs used could carry the heaviest loads and failed to remove sub-standard TSAs when warned.

"This was a safety-critical component and was likely to be used in safety-critical circumstances," explained Mr Ageros.

Describing the incident as a tragic accident, Judge Hazett Colgan said: "The TSA was down-rated and should not have been used for a slab of that weight, and had been marked in red paint to show this.

"SGB knew about the poor quality of some of them and they re-supplied down-rated TSAs to four sites around the country."

Following the verdict, A SGB spokeswoman said: "We greatly regret that our components were part of the structure that failed and everyone at SGB was greatly affected by the tragedy that occurred. Everyone involved from SGB sends its sincere condolences to Matthew Gilbert's family and hopes also that Mr Singh has been able to make a good recovery.

"We acknowledge that we should have had better systems in place in 2003 to ensure that the substandard TSA's were not supplied in the first place.

"We would like to make it clear that we have taken measures to prevent a similar situation happening again."