Controversial plans to merge the police forces of England and Wales will cost the taxpayer nearly £800 million - equivalent to the wages of almost 40,000 young constables, according to a new report.

The hidden costs of the Government's plans to create 'superforces', according to a study produced for chief constables, are more than previously thought and could plunge the service into a major cash crisis.

The Home Office has proposed a merger of the West Midlands, Staffordshire, Warwickshire Police and West Mercia forces but the latter is insisting that remaining separate would be best.

It is now feared that Government plans will lead to a major drop in the money the police receive from council tax.

A recent paper prepared by Tim Brain, the chief of Gloucester and leader on finance issues for the Association of Chief Police Officers (Acpo), suggested the costs would run to more than £500 million, the "cash equivalent" of the annual salary of 25,000 probationary constables.

This projection was dismissed by Ministers as a "worst case scenario", a claim disputed by Mr Brain and his team.

The "25,000 officer" estimate was based on the likely "set up" expenses of reducing 43 forces to about 17 - such as redundancy pay-outs - and budget shortfalls due to expected reduced Government grants to police from 2008.

However, Mr Brain's team have calculated that forces are likely to lose a further £286 million - the yearly cash equivalent of another 14,000 probationary officer salaries - in a process dubbed equalisation."

Home Secretary John Reid recently announced he would delay mergers at least until the autumn. But "precept equalisation" will remain a major stumbling block. The precept is the contribution made from local council tax to policing any area, above the central Government grant.

In the case of the one agreed amalgamation - between Lancashire and Cumbria - which it is assumed will be applied to other cases, Mr Brain's research shows over five years there would be a funding shortfall.

Observers in the police world believe this is an example of two Government policies coming into conflict.

Mr Brain is due to present his latest work to Acpo but in an article in House, the magazine for MPs, he wrote: "Restructuring will be the biggest event to hit the police service in almost 40 years.

"The combined effects of restructuring and budget cuts could mean losing the cash equivalent of 25,000 probationary constables. Current Home Office plans for restructuring 'precept equalisation' could add the cash equivalent of almost another 14,000.

"Something will have to give - neighbourhood policing, restructuring, major projects?" ..SUPL: