Tony Blair was challenged last night to prove he did not mislead MPs over the appointment of a former special adviser to Geoff Hoon, the Defence Secretary, to Brunswick, a public relations company with military clients.
The Prime Minister told MPs that Andrew Hood's move had been approved "in consultation with the Cabinet Office in the normal way".
But Mr Blair's insistence appeared to contradict an earlier assertion by a Cabinet Office spokeswoman that it had not been involved in the process at all. Later it modified its comments to say it had discussed the appointment informally with the Ministry of Defence.
Opposition MPs said the Government appeared not to have followed Civil Service rules, which require contentious appointments to be cleared formally with the Cabinet Office.
Tim Collins, the Tory Cabinet Office spokesman, said: "Many people were very surprised indeed that Tony Blair told the Commons on Wednesday the MoD had consulted the Cabinet Office over this, when earlier journalists had been briefed that they had done no such thing.
"If he is not able to produce any evidence to back up his assertion, this will be yet another example of a story about special advisers turning into a story about the Prime Minister misleading Parliament."
Charles Kennedy, the Liberal Democrat leader, wrote to Downing Street last night asking Mr Blair to spell out the background to the case.
Mr Kennedy said: "Your statement in the House of Commons would appear to be at variance with the statement of the Cabinet Office spokeswoman on this issue.
"In order to end this confusion, could I ask you now to clarify whether the Cabinet Office was formally consulted over this appointment and to confirm that this in no way breached the Civil Service Management Code?"
He said the appointment was "a rum business to say the least". He added: "Given the Government are hogging the headlines with bad headlines at the moment, they don't seem to get their internal communications, let alone external communications, very good."
Robin Cook, the Leader of the Commons, told MPs that Mr Hood's appointment had been approved "in the normal way". He added: "The Cabinet Office was consulted about the procedure."
Downing Street said there was no change in the Prime Minister's position. A spokeswoman added: "The Cabinet Office was asked about the process, but not to make the decision."
Brunswick has said that Mr Hood has accepted a managerial post, which will not involve meeting its clients, who include the defence contractors Rolls Royce and Vickers.
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