Maria Wallis's fall from favour

The decision by Maria Wallis follows revelations by the BBC on Tuesday that senior figures in the Police Authority were calling for her resignation.

Mrs Wallis, 50, said her immediate retirement was "the right thing to do for the people of Devon and Cornwall".

A Police Authority spokesman said there had been no edict for her to leave and deputy chief constable Nigel Arnold would take interim charge of the force.

Sources told the BBC the authority had lost confidence in her management of the force.

'Great sadness'

In a statement released on Wednesday, Mrs Wallis said the last two months had been "very challenging personally" after the death of her mother last month and her father undergoing a major operation.

She said: "I have always put the needs of the force first. It is for this reason that I announce with great sadness my immediate retirement.

"It has been an honour and a privilege to have been the Chief Constable of Devon and Cornwall Constabulary for the last four years.

"I am enormously proud of the achievements of our staff, in particular the recent excellent performance.

"I have been pleased to lead on the positive improvements we have made in Devon and Cornwall."

Independent inquiry

Devon and Cornwall Police Authority chairman David Money said the retirement had asked for formal retirement as a result of discussions that took place on Wednesday.

Mr Money said that in recent years there had been damage to the confidence of staff, police officers and the community.

"We need to repair this damage and restore confidence.

"We must not forget the work of Maria Wallis has been hugely impressive, and perhaps we came to the point that for all our sakes a change was desirable."

Mrs Wallis was facing an independent inquiry into a pay review last year.

The force backed down over the review which Mrs Wallis authorised and proposed cutting hundreds of civilian workers' salaries.

The investigation, announced on Tuesday by the Independent Police Complaints Commission, is the sixth into the pay review.

The force said the pay review had been designed to ensure staff were paid fairly.

Mrs Wallis, who joined Devon and Cornwall Police in 2002, angered detectives in 2004 in a row over pay and resources during a series of murder cases and some withdrew out-of-hours cover in protest.

A row erupted over putting pictures of officers on the force website

Rank and file were also angered after some beat officers' photographs were published on the police website in a move to raise their local profile in 2004. Legal action was threatened before a compromise was reached.

Mrs Wallis has also been responsible for an increase in the number of local beat officers since she joined.

Earlier this month figures showed the force had the fourth largest reduction of total crime nationally, down 7% between April 2005 and March 2006 against a national average of 1%.

Exeter MP Ben Bradshaw said he "regretted" the chief constable's decision.

"I think Maria Wallis has done an extremely good job at getting crime down considerably, achieving a record number of police officers and the extension of community patrol officers."