A FULL ­independent public inquiry into offshore helicopter safety has been demanded by MPs after they heard claims of a culture of "macho bullying" of worried North Sea workers.

Rig workers were told by company officials to put on "big boy pants" or quit the industry if they could not deal with the risk just weeks before a fatal crash off Shetland, a damning report published today by the Commons Transport Committee has revealed.

The report refers to "troubling evidence about a macho bullying culture in the oil and gas industry".

MPs concluded that an inquiry was needed to establish if commercial pressure from oil and gas companies was affecting the safety of offshore helicopter operations. They said more must be done to "facilitate a culture of approachability and openness at all levels".

The issue was examined ­following the tragedy last August, when four passengers were killed as the Super Puma helicopter in which they were travelling crashed into the sea while on approach to Sumburgh Airport.

The incident led to a review by the Civil Aviation Authority (CAA), which in February made recommendations on safety governance, airworthiness and equipment. However, MPs noted it had not looked at the impact of commercial pressure on helicopter safety.

Committee chairwoman Louise Ellman MP said: "After four accidents in five years, offshore workers' confidence in helicopter safety is understandably low. Despite work by the CAA, serious questions remain unanswered about offshore helicopter safety in the competitive commercial environment of the North Sea. We fear a creeping complacency may be affecting safety standards.

"The role and effectiveness of the CAA has not been adequately examined. Only a full and independent public inquiry would have the power and authority to investigate properly."

Mick Cash, acting general secretary of the RMT union, said the accident was an explicit illustration of how offshore workers' safety was compromised by helicopter operators, who were not held to effective, industry-wide standards, including in the contractual relationship with the oil and gas companies.

He said: "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."

Jim McAuslan, general secretary of pilots' union Balpa, also said the report added further weight to an urgent need for safety improvements and backed the call for a public inquiry.

Frank Doran, Labour MP for Aberdeen North, welcomed the report, noting he had been particularly concerned about the "commercial pressure placed on helicopter operators" and the CAA's "light touch approach" to regulation of the offshore helicopter industry.

He added: "I know from my contact with workers offshore there is still deep concern about health and safety in this area. Only a full public inquiry will give the workforce and their families the confidence that they desperately need."

The Department for Transport said it was working closely with the CAA on safety issues, stressing it was "vital offshore workers are able to operate in a safe environment". It added that it would respond formally in due course.

In the report, the MPs highlighted how the Air Accidents Investigation Branch investigation into the Sumburgh crash uncovered a number of "deeply worrying" issues; in particular, it found the pre-flight safety briefing did not accurately explain how to use the type of emergency breathing system supplied on the helicopter.

Ms Ellman explained: "Survivors of the 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 it took a fatal accident in such circumstances before inadequacies in safety briefing were identified."