West Midlands Police has been hit by a bill for half a million pounds for the Conservative Party conference, at the same time as it is making hundreds of front line officers redundant.
The cash will have to be come from council taxpayers or by making cuts.
But the force is already set to lose more than 1,000 police officers by 2015 as it struggles to cope with budget cuts of s112 million.
The fee is a result of changes to the way the Home Office funds policing for major national events.
Traditionally, it paid the entire cost from a fund known as the Special Grant, to ensure police forces werent forced to cut back on crime-fighting to pay for special events.
But earlier this year, the Home Office announced it was only willing to pay 85 per cent of the costs.
It meant West Midlands Police will not receive a full refund for the cost of policing the Liberal Democrat conference last year, and has been forced to pay s249,942 out of its own funds.
And it will also have to contribute s500,000 towards the s3.3 million cost of policing the Tory event in Broad Street last week.
West Midlands Police Authority has written to Policing Minister Damian Green urging him to intervene, as well as to police authorities in Manchester, Liverpool and Brighton, which also hosted party conferences over the past two years, suggesting they work together.
Bob Jones, Labours candidate for police and crime commissioner in the West Midlands, said: It was a national event and it should be funded nationally. Instead, we have to cough up half a million pounds when were already being forced to make massive cuts.
He added: This is potentially the salary of 15 police officers being lost for the joys of bringing the Tory conference to Birmingham.
The high profile event at the International Convention Centre was overshadowed by the row over Conservative MP Andrew Mitchells confrontation with police officers in Downing Street.
Representatives of the Police Federation protested against funding cuts wearing PC Pleb T-shirts.
A Home Office spokesperson said: Police authorities in areas that host a political party conference are provided with a special grant to assist with the costs.
We are currently reviewing the policy to ensure policing measures are proportionate to the level of threat and provide value for money for the taxpayer.
Ministers came under fire in the House of Commons from critics of the police commissioner elections, as Labour MPs demanded to know how much had been spent on a series of television advertisements and posters designed to boost turnout for the ballot on November 15.
Ministers confirmed that s75 million had been spent on the election process as a whole, but Black Country MP John Spellar (Lab Warley) told MPs: What the minister did not say was how much extra, over and above that, the Government is going to spend on adverts to try desperately to get people out to vote in these unwanted elections in the middle of November.
Why is the Government not holding the elections at a sensible time and spending the money on front-line police officers?
Mr Green replied: The elections may be unwanted by him, although I suspect that they will be less unwanted by some of his Labour colleagues; at the last count, seven former Labour ministers were standing in the police and crime commissioner elections.
I am genuinely surprised that the right honourable gentleman is so afraid of democracy. On the whole, during its history the Labour Party has welcomed advances in democracy. It is a sad comment on the state of the modern Labour Party that it should be frightened of democracy.
Theresa May, the Home Secretary, offered her backing to proposals from the Conservative candidate in the Staffordshire force area, Matthew Ellis, to provide iPads to every police officer.
She was asked by MP Christopher Pincher (Lab Tamworth): Does she agree that the innovative use of modern technology, such as that proposed by the police and crime commissioner candidate for Staffordshire, Matthew Ellis, which could cut up to 3,000 hours of police administration time each week, will help forces such as mine put more officers on the beat to fight crime and reassure the public?
Ms May said: I agree with my honourable friend. I have been in Staffordshire with our excellent Conservative candidate, Matthew Ellis, who has some very good proposals for helping the police to do their job and tackle crime, one of which is getting rid of bureaucracy by using new technology.
Labour claims the scheme would cost more than s1 million and lead to even more job losses.