“Creeping complacency” is putting offshore workers’ lives at risk, a panel of MPs warned yesterday following a slew of trade union testimony.

Backbenchers on the Commons transport committee will demand a “full, independent public inquiry” from coalition ministers today amid longstanding concerns about the safety of oil and gas workers as helicopters ferry them to and from Britain’s offshore drilling platforms.

The MPs’ plea began with an investigation in the wake of last August’s fatal Super Puma crash in the North Sea near Shetland, the fifth such ditching involving the North Sea fleet since 2009 and the second to cause deaths.

But while they found no conclusive evidence that Super Pumas were less safe than other helicopters, Labour chairwoman Louise Ellman said “serious questions remained unanswered” about operators’ commercial pressures to cut costs.

Ms Ellman said offshore workers’ confidence in the industry’s safety record was “understandably low.”

She said: “We heard troubling evidence about a macho bullying culture in the oil and gas industry, including that offshore workers who were concerned about helicopter safety were told that they should leave the industry.

“Survivors of the (2013) Sumburgh crash told us that they did not use the emergency breathing system provided on the helicopter because the information given to them by the safety video was flawed.

“It is appalling that it took a fatal accident in such circumstances before inadequacies in safety briefing were identified.”

Transport union RMT acting general secretary Mick Cash strongly backed the appeal, saying the coalition had “no excuses” to ignore calls for an independent inquiry.

He said: “The tragic incident off Sumburgh in which four offshore workers lost their lives was an explicit illustration of how offshore workers’ safety is compromised by helicopter operators who are not held to effective, industry-wide standards, including in the contractual relationship with their customers — the oil and gas companies.”

“There are now no excuses for the government, helicopter operators or oil and gas companies. They must take clear and immediate steps to reduce the threat to offshore workers’ safety from helicopter transport, reduce accident rates, improve survivability and listen to offshore workers’ concerns about the safety of the helicopters they rely on.”