The decision on process has nothing to do with the merits of Ms Filkin

Robin Cook

Leader of the Commons Mr Cook told MPs that the fact Ms Filkin was in the running for the job showed she had done well in her post.

It is widely speculated that Ms Filkin caused annoyance in some quarters during the course of a series of vigorous investigations into complaints against some MPs.

Her probe into the affairs of former Europe Minister Keith Vaz lasted months and caused the government embarrassment ahead of the general election.

Mr Cook said: "The decision on process has nothing to do with the merits of Ms Filkin.

Mr Cook said she had been good at her job

"She has done a good job, that is why she is a candidate, and if she is the best candidate she will be offered a further contract if she wishes."

It was not unusual to require people on fixed term contracts to reapply for their jobs - ambassadors were just one example, Mr Cook said.

He added that the decision, which was taken by the House of Commons Commission, would ensure that the best candidate got the job.

'Slightly odd'

"I find it slightly odd that there have been accusations that this is a closed decision when actually we have gone for an open process."

When it was first announced that Ms Filkin had to reapply some MPs complained that the move would create a poor impression outside parliament.

Labour MP David Winnick said: "The message that will come across, intended or otherwise, is that there is a majority in parliament across all parties who don't want to have someone as a watchdog who is very effective and moreover who looks into cases regardless of (an MP's) seniority."