Controversial spin doctor Jo Moore and Transport Department Press Chief Martin Sixsmith last night paid the price for their bitter feuding as both quit their jobs.

Transport Secretary Stephen Byers announced he had accepted their resignations after being ordered by Downing Street to end the "civil war" raging inside his department, which had rocked the whole of Whitehall.

Mr Byers, MP for North Tyneside, acknowledged there had been a "breakdown of trust" within the Department of Transport, Local Government and the Regions (DTLR) and said that Ms Moore and Mr Sixsmith had done "the right thing" in resigning.

However, the announcement brought immediate demands from the Tories for Mr Byers to quit too.

"It is perfectly clear that Stephen Byers cannot run his own office, let alone a transport network," said Shadow Transport Secretary Theresa May.

It had been clear from early in the day that one or both would have to go after the Downing Street press office was dragged into the extraordinary feud between Ms Moore - a Labour Party appointee - and Mr Sixsmith, a member of the permanent Civil Service.

In her resignation letter to Mr Byers, Ms Moore blamed "individuals" within the DTLR who were not prepared to work with her and whom she accused of inventing stories about her.

In the letter, addressed to "Dear Steve", she said she had hoped to be able to continue her work as normal after her "heartfelt apology" for her September 11 e-mail, but now accepted that it was not possible.

"Clearly there are some individuals in the department who are not prepared to work with me and are even prepared to invent stories about me, as they have done this week," she wrote.

"I have devoted most of my adult life to working for the Labour Party because I am committed to achieving a fair and just society. I do not want to be an obstacle to achieving this goal."

The row broke on Thursday with the apparent leak to newspapers of an e-mail from Mr Sixsmith to Ms Moore warning he would not allow any sensitive announcements to be "buried" on the day of the royal funeral.

Initially it was dismissed by the DTLR as a "fabrication" - a line repeated that morning by the Prime Minister's official spokesman Godric Smith, in a briefing to political journalists, given after consulting with Mr Sixsmith, a former BBC correspondent in Moscow.

However, news organisations later discovered that an e-mail had been sent.

That drew a furious response from Mr Smith, who made clear his anger at being put in a position where he had released incorrect information.

Liberal Democrat chairman Mark Oaten condemned the announcement's timing. "We should not be surprised that this resignation finally came at 5pm on a Friday before a Parliamentary recess and on the day of a Royal funeral," he said.

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