Reporter's immediate superiors could be in the firing line for bad judgement

The BBC executives whose positions are most at risk are those who worked most closely with Andrew Gilligan.

Most vulnerable is Kevin Marsh, the editor of the Today programme, that chose to broadcast Gilligan's sensitive report in the form of an unscripted "two-way" exchange with the presenter John Humphrys.

Mr Marsh appears to have had concerns about Mr Gilligan's working methods and yet there was an apparent failure to check the strength of the report in the seven days between the reporter's interview with the scientist Dr David Kelly and the report's broadcast.

Although the BBC initially defended its story, Mr Marsh warned Stephen Mitchell, the head of radio news, in an e-mail written a month after the broadcast, that Gilligan's work was "flawed" and had involved "loose use of language" and "lack of judgement".

BBC governors had privately said that the culture of the Today programme had "moved in line with tabloid and Sunday newspaper journalism where contacting people who might deny a story were avoided".

Further up the BBC chain of command is Richard Sambrook, the director of news, who had a responsibility for the system of checks and balances. Mr Sambrook has admitted the story should have been scripted and checked by a lawyer before broadcast.

One experienced television executive said: "If you are going to do difficult journalism, make sure your systems and journalists are up to it. You can blame Sambrook for not having effective systems."

Mr Sambrook also blundered by publicly stating that the story was based on information from an intelligence source. He did not realise that was not the case until a month after the report.

Jonathan Sumption QC, said: "Mr Sambrook realised by 27 June that the source was not a member of the intelligence services, and nevertheless allowed the impression that he was, to persist even among the Governors of the BBC."

Gavyn Davies, the BBC chairman, also has reason to be nervous. He led the BBC's defiant stance, for which he was applauded. He may now wish he had followed a course of action suggested by the senior governor, Dame Pauline Neville-Jones, and referred the Government's grievance to the BBC's complaints unit.