The senior civil servant at the heart of the Jo Moore affair has signalled it was Stephen Byers and Tony Blair who decided she should keep her job after her infamous e-mail.

Sir Richard Mottram was giving evidence on the last day of hearings in an inquiry into the role of special advisers.

If we want to solve a problem then special advisers can be a very useful network to think of measures

Lord Macdonald Cabinet Office Minister

The former transport permanent secretary said it had sometimes been presented as if he had determined Ms Moore should stay after she suggested 11 September was a "good day to bury bad news".

"I do not think anyone seriously thought it was the disciplinary process," Sir Richard told the Committee for Standards in Public Life's inquiry.

He was asked whether the secretary of state in a department was accountable for disciplining a special adviser in such a case.

'Wrong question'

Sir Richard replied: "In a case of that kind, I think it is the secretary of state and the prime minister."

The civil servant, who is now permanent secretary of the Department for Work and Pensions, had been asked what penalties a civil servant would face in such a case.

Mottram now works in transport department

But he said that was "in a sense an answer to the wrong question" - arguing that the reason why the Jo Moore controversy dogged the transport department for so long was because she was not a civil servant.

Ms Moore later resigned, along with Martin Sixsmith, the transport media director with whom she had clashed.

The episode eventually saw Mr Byers himself leave his cabinet post.

Praise

At the time, ministers said Ms Moore had made a terrible error of judgement but said she had been dealt with through the right disciplinary procedures.

Sir Richard has already told a Commons committee that the decision to keep her in her job was made above his level.

He insisted there was a legitimate role for politically appointed special advisers in government to do things civil servants could not and bring new viewpoints.

Care was needed for permanent secretaries to induct outsiders into government's public service ethos, he said.

"In the case of one special adviser I suppose I did not do that brilliantly," he added.

That view was voiced earlier on Wednesday by Cabinet Office Minister Lord Macdonald.

Lord Macdonald told the committee's inquiry: "If we want to solve a problem then special advisers can be a very useful network to think of measures and a useful shortcut."

Having heard from 48 witnesses, the Wicks Committee will now work on producing recommendations about where the boundaries should lie between civil servants, ministers and special advisers.