The full extent of the row between the Commons watchdog and the Speaker has been revealed.

In a series of letters between the pair revealed on Tuesday, Speaker Michael Martin accused Elizabeth Filkin of failing to prove allegations of a whispering campaign against her.

He claimed her documents "identify no names and do not provide the evidence which your allegations would lead one to expect".

Filkin, who refused to reapply for her job as parliamentary standards commissioner, hit back saying her request for an urgent meeting with Martin to discuss the independence of her post had been ignored.

She complained after her job was downgraded and reduced to three days a week. When her contract was brought up for renewal MPs informed her that she would have to reapply.

Filkin claimed senior members of the government were briefing against her to the media in revenge for her investigations of Peter Mandelson, Geoffrey Robinson and Keith Vaz.

She quoted a former Labour chief whip who advised her to "watch out" in the wake of her investigations into complaints about high profile MPs.

Filkin refused to offer names to avoid breaching confidences but quoted the late Lord Cocks who told her: "You should look after yourself, you need to watch out ... A lot of stuff is going to hit the fan soon."