The first sign that ministers are considering a U-turn on the issue came when government lawyers dropped an injunction to prevent the BBC showing a Panorama interview with Mr Shayler on Friday night.
The former MI5 man, currently in a Paris prison awaiting extradition, accused the secret service of plotting to kill Colonel Gaddafi. The allegations were let through after parts of the interview said to endanger the lives of serving officers were deleted.
Panorama insiders, however, said that the Government's tone changed dramatically from Thursday, when it was clear they wanted a blanket ban, to Friday, when they were prepared to compromise.
It is thought that among the MPs putting pressure on the Government to soften its line was Clive Soley, chairman of the Parliamentary Labour Party, who is known to have strong misgivings about the whole Shayler affair.
Critics of the Government's hard line say that the alleged Gaddafi plot took place under a previous administration and that MI6, which is the arm of the secret service which operates abroad, was "out of control".Reuse content