More than 3,000 of the most experienced police officers could be forced to retire early under a legal loophole, figures showed today.

A total of 3,260 officers with 30 years' experience or more could be affected by plans by some forces to take advantage of the cost-cutting move which enables them to force officers to retire, the figures released by Home Secretary Theresa May showed.

Under regulation A19, which is contained in the Police Pensions Regulations 1987, officers who have served 30 years or more can be "required to retire" if their retention would "not be in the general interests of efficiency".

The figures include 1,154 in the Metropolitan Police, Britain's largest force, 244 in the British Transport Police and 198 in the West Midlands force.

Shadow home secretary Ed Balls wrote to Mrs May today, asking what guidance she plans to give to police forces and authorities on the use of the regulations and how many forces she is aware intend to use them.

He also asked what consideration she has given to the impact of losing "a disproportionate number of highly experienced police officers".

Mr Balls said: "People are rightly concerned that 20% funding cuts being demanded by the Government will see fewer police officers and undermine the fight against crime.

"But it is very worrying that the scale and pace of the coalition's cuts mean that we could lose thousands of the most experienced officers in the country.

"This would be madness, but the Government is putting police forces in an impossible position.

"A number of forces have already said they may have to take this drastic action, but with big cuts on the way I fear this could be just the tip of the iceberg."

The Police Federation, which represents rank-and-file officers in England and Wales, warned earlier this month that the regulation, which applies to all police below chief officer rank, regardless of ability or age, was a "blunt instrument" for forcing hundreds, possibly thousands, of officers to go.

Simon Reed, the federation's vice-chairman, said the regulation was designed to enable forces to remove the odd officer who, having been in the job for 30 years or more, was perhaps cruising and not performing efficiently.

The police service needs to cut its wage bill after the Government said funding will fall by 20% over the next four years.

The spending cuts, coupled with the forced retirements, mean "the future is challenging and very depressing for the police", Mr Reed said.

The Association of Chief Police Officers (Acpo) said chief constables "have difficult choices ahead".

Surrey chief constable Mark Rowley said that while the decision to invoke regulation A19 was "difficult", it was "currently the only option available to police forces to reduce police resources, and invoking it will ultimately save £2.2 million".

A force-by-force breakdown of the figures is available on Hansard at: