"Unfounded accusations" had taken their toll on Mr Hayman he said

Metropolitan Police Assistant Commissioner Andy Hayman had come under increasing scrutiny after the death of Jean Charles de Menezes.

A recent report found he misled the public in the immediate aftermath of the Brazilian's shooting.

He has also been asked to explain �15,000 worth of expenses.

Mr Hayman, 48, headed the Met's special operations unit, which is responsible for anti-terrorism investigations.

'Very hurtful'

"Recent weeks have seen a series of leaks and unfounded accusations about me, which I have and will continue to refute strongly," he said.

"However, these events take their toll on you personally and I feel now is the right time for me to step aside."

His leadership had come into question following the shooting of Mr de Menezes at Stockwell Tube station in south London in July 2005.

A report from the Independent Police Complaints Commission (IPCC) found inconsistencies between what Mr Hayman had told a crime reporters' briefing and a Metropolitan Police Authority management meeting on the day of the shooting.

Forced to apologise

A spokesperson for Jean Charles de Menezes's family said: "We welcome the fact that Andy Hayman is no longer in office given he was found to have deliberately 'misled the public' after the shooting of Jean Charles de Menezes.

"His resignation is a further indictment of the attempted cover up by the Met after Jean's killing."

He was forced to apologise over an anti-terror police operation in Forest Gate, east London, when officers shot an innocent man in June 2006.

Born in 1959, father-of-two Andy Hayman reached the third highest rank in the Met through uniformed and CID posts in Essex and London.

He joined Essex police in 1978, where he served as a uniformed officer in the criminal investigation department.

In November 1998 Mr Hayman was appointed Commander in the Met and given responsibility for drugs, crime and complaints investigations.

In September 1999 he was appointed director of what is now the Directorate of Professional Standards, responsible for discipline and anti-corruption.

From April 2001 to December 2002 he was deputy assistant commissioner, retaining responsibility for professional standards and assuming extra responsibilities as deputy to the deputy commissioner.

In 2002, he was appointed Chief Constable of Norfolk constabulary before returning to London as assistant commissioner for specialist operations in 2005.

Mr Hayman was awarded the Queen's Police Medal (QPM) in the Queen's Birthday Honours June 2004 and a CBE in the 2006 Queen's Birthday Honours list.

Peter Clarke, the current head of the national Counter Terrorism Command, has postponed his own retirement to take on Hayman's role temporarily until a replacement is chosen.