Police officers were paid £412million in overtime last year - more than ten times what the Government saved by refusing to back-date their pay rise.

The astonishing bill, which has more than doubled since Labour came to power, piled further pressure on Jacqui Smith.

The Home Secretary saved around £40million by not backdating a 2.5 per cent police pay offer to September.

But critics said she could have saved far more by reducing bureaucracy to cut the overtime bill - without alienating huge numbers of rank-and-file officers.

The Government employs 14,000 more police than ten years ago, which should have led to the overtime bill going down as the workload was shared out.

But instead average payouts have spiralled from £1,500 per officer to nearly £3,000 last year.

One force, Northumbria, paid its officers almost £5,000 each.

In contrast, the pay rise being held back by Miss Smith is worth less than £20 per officer.

Officers are threatening to ballot for strike action over the dispute and a rally is due to take place in London later this month.

Conservative police spokesman David Ruffley said: 'This overtime is being used to do ever more paperwork.

'Red tape on our police is increasing and it is wrong that police spend more time on paperwork than on patrol.' Other factors behind the rise include antiterror operations and officers being forced to guard convicts in station cells because there is no room in prison.

Matthew Elliott, chief executive of the TaxPayers' Alliance, said: 'Political meddling and mismanagement of the police is costing the taxpayer dearly.

'Understaffing, excessive red tape and being forced to plug the holes in the prison service are all taking their toll.

'People want the police to be able to catch criminals and keep people safe - instead, crime is rising and police are paying record amounts of overtime just to try to keep up with the Government's demands.'

Alan Gordon, vice chairman of the Police Federation, said: 'The increase is so substantial that the main link is likely to be with the increased pressures being placed on the service, particularly the fight against terrorism.

'That is a colossal commitment. If police are away from their normal duties to police the transport infrastructure and that sort of area, overtime will be used to try meet these demands.'

But he added that bureaucracy was also a factor, with arrests taking longer than ever to process. This leads to officers having to stay on duty beyond their shift.

Mr Gordon added: 'There is an awful lot of concern about the exorbitant hours that officers are being expected to work because of the increased demands.

'A lot say, "We do not want to work all this overtime, we want a work-life balance".'

The latest figures show police are spending more time than ever filling in forms.

Some 19.7 per cent of their working day is spent on bureaucracy such as filing crime reports, preparing for court, writing letters and sending memos.

Only 13.6 per cent is spent on patrol, according to statistics uncovered by the Tories.