A gas expert from the UK has said if a test which checks for leaking gas had been done an explosion at a block of flats, which killed ten people, would not have happened.

Chris Clarke is giving evidence in the trial of gas workers Neil Armstrong, John Wright and Lee Ward who deny 10 counts of gross negligence manslaughter.

In a combined case, Island Energy has pleaded not guilty to health and safety breaches.

The workers were excavating gas pipes on the road below the Haut du Mont flats that serviced the area of La Collette - including the flats - on 9 December 2022, the day before the explosion.

The court previously heard the men had been decommissioning the gas pipe that serviced the flats, but the pipe was cut wrongly and cut off supply to other properties.

In a police interview heard in court earlier, Wright told officers he had been told to lie about doing a pressure test - which checks for leaking gas.

When asked by defence advocate for Island Energy Mike Preston if not doing a pressure test was the most serious failure, Clarke said it "would've been the one that would've prevented this [explosion] happening".

The residents who died were Peter Bowler, 72, Billy Marsden, 62, Derek Ellis, 61, Sylvia Ellis, 73, Ken Ralph, 72, Jane Ralph, 71, Romeu De Almeida, 67, Louise De Almeida, 64, Raymond Brown, 71, and Kathy McGinness, 73.

Clarke also told the court that Island Energy's instructions on how to cut a gas pipe were "very straightforward to follow" and "perfectly adequate".

"I think its clear that those procedures weren't followed," he told the court.

Speaking about the accuracy of the plans in the gas industry sometimes not being up to scratch, Clarke told the court he believed the ones he had seen for La Collette had been "generally accurate" but "not precise".

The jury was told by Clarke that the size of the hole at the excavation site which gave the gas workers access to the pipes was not large enough.

He said: "Clearly it wouldn't be large enough to do bagging off... it should be twice that size if you're going to be able to fit four bags in it which the IE procedures require."

"Bagging off" is an engineering technique used to temporarily block the flow of gas in an active pipeline.

The trial continues.

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