Boris Johnson’s administration in the capital suffered a severe blow yesterday when Tim Parker, the most senior member of his team, quit abruptly, only weeks after taking up his post.

In the latest staffing controversy to engulf the Mayor of London, Mr Parker — a City executive with a slash-and-burn reputation — resigned as first deputy mayor and chief of staff.

His departure is particularly embarrassing for Mr Johnson because it follows two other high-profile resignations during the first 100 days of his mayoralty, raising questions about his judgment, experience and the quality of his administration.

Yesterday both Mr Johnson and Mr Parker insisted that their parting had been mutually agreed, although sources told The Times that there had been clashes between the millionaire businessman and other senior advisers at City Hall.

Mr Parker, the controversial former boss of the AA, Kwik-Fit and Clarks shoes, was hired to streamline the Greater London Authority and to run Transport for London (TfL) from next month. The man nicknamed the “Prince of Darkness” for overseeing thousands of job losses in the private sector, resigned after it was decided that Mr Johnson would retain the transport chairmanship. It represented a significant downgrading of the job that Mr Parker was hired to do.

He said yesterday that it was not appropriate for an unelected official to chair the body, given that transport involved enormous sums of money and was such a large part of the mayor’s brief. “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, or the title of first deputy mayor.” He will continue serving as an unpaid adviser and will stay as a member of the TfL board.

His resignation shocked onlookers because his appointment had been considered a coup for Mr Johnson’s administration. The mayor had highlighted Mr Parker’s ability to make companies more efficient.

Before taking up his role, Mr Parker told The Times that he intended to work with Mr Johnson for the first four years of his administration.

There was speculation that, as a top businessman accustomed to running his own show, Mr Parker had become frustrated quickly by the public sector. The Times was also told that he had already clashed with the Tory borough councillors, including former Westminster leader Sir Simon Milton, over his vision for job cuts.

A source said: “There have been disagreements and that was inevitable. Tim Parker wanted a cost-cutting drive and Boris Johnson and Sir Simon were more cautious about the kind of savings that you can get in the private sector. Those are the kind of efficiencies that make elected people uncomfortable.”

Mr Parker was hired for the nominal salary of £1 per year.

The resignation will increase the pressure on Mr Johnson, who has faced significant criticism early in his leadership over his hiring procedures. Ray Lewis, the deputy for youth at the centre of Mr Johnson’s bid to fight knife crime, resigned after he was forced to deny allegations of inappropriate conduct and financial irregularities in his past. James McGrath, the mayor’s senior political strategist, quit over a race row.

Critics said yesterday that the resignation highlighted the mayor’s inexperience and that he should have been aware of the political nature of the TfL role. Ken Livingstone, the former mayor, chaired the board throughout his term in office.

Mr Johnson would only say that Mr Parker had done a “fantastic job” and had produced a “useful restructuring programme” for the GLA. “He is not lost, he is translated into a new and different identity to continue to be of great service to us,” he said. “There are big decisions I have to take as mayor about transport. They are intensely political decisions. Over the last few weeks and months, Tim and I realised that I had to chair TfL and there was no value in his occupying that intermediary position.”

The London Assembly Labour Group said that Mr Johnson was in an unsustainable position and had brought City Hall into disarray.

The series of departures at City Hall is being watched with growing nervousness by senior Conservatives. Mr Johnson’s administration has been viewed as a test for national policy.

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