LONDON (Reuters) - Tim Parker, London Mayor Boris Johnson's First Deputy, quit his post and the job of running the capital's transport network on Tuesday, the third senior aide to leave the administration in three months.
Parker, a former private equity executive, was appointed First Deputy Mayor after Johnson's election victory for the Conservatives in May and was due to take over as chairman of Transport for London (TfL) in September.
Unions had expressed concern that Parker, who built up a reputation for ruthless cost-cutting during previous roles at motoring group the AA and at car-repair firm Kwik-Fit, would put jobs at risk.
However, Johnson said he would now take on the job of running TfL with Parker becoming an adviser, meaning his position as deputy mayor was no longer appropriate.
"Over the last few weeks, it has become increasingly apparent to both of us that the nature of the decisions that need to be taken are highly political and there is no substitute for me, as the directly elected mayor, being in charge," the mayor said in a statement.
Parker is the third senior official to leave Johnson's fledging administration since his win over Ken Livingstone.
In July, Deputy Mayor Ray Lewis resigned amid intense media scrutiny of his past and allegations of sexual and financial misconduct.
That came after James McGrath, a senior adviser to Johnson, was forced to quit in a race row after he made disparaging remarks about people from the Caribbean.
Parker will stay on as an adviser on transport issues but said it would have been inappropriate for him to chair Tfl as an unelected official or stay as Chief Executive of the Greater London Authority.
"I also agree with the mayor that my position as adviser does not justify my full-time and exclusive commitment to the Greater London Authority (GLA), or the title First Deputy Mayor," he said.
"We have therefore decided to adjust the management structure and abolish that position."
Jeanette Arnold, the Labour chairman of the GLA, said the decision was welcome.
"The assembly's role is to hold the mayor to account on behalf of Londoners and ... we will be looking closely at this seemingly shambolic situation to ensure it doesn't affect the mayor's ability to run London effectively," she said.
(Reporting by Michael Holden; Editing by Steve Addison)