A former boss at the Health and Safety Executive has said the body is "grossly inefficient" and "dysfunctional".
The HSE is throwing up barriers to rail safety, a former director claims
Alan Osborne, who quit as director of rail safety at the agency last month, said internal politics and turf wars had hampered him in his job.
In his resignation letter, leaked to the Economist magazine, he also said the HSE tended to come up with inappropriate and costly ideas for safety problems.
He concluded that the body should lose its responsibility for railway safety.
Mr Osborne said he had felt unable to implement crucial recommendations from the Cullen report on railway safety because of such turf wars and in-fighting.
The Cullen inquiry was set up after a total of 38 people perished in the late 1990s during two separate head-on crashes - at Ladbroke Grove and Southall.
"I began to hit so many barriers within the HSE that I came to the conclusion that it was not possible to meet Lord Cullen's vision for the HSE's rail activities," he said.
Some ministers are understood to share his concerns about the authority.
The Economist believes a shake-up may be on the way.