Policing the Tory conference will cost the cash-strapped West Midlands force £500,000, it has emerged.

Police and crime commissioner Bob Jones warned the bill – prompted by Home Office funding changes – would add to the organisation’s financial problems.

He has written to Home Secretary Theresa May insisting the cost would hit West Midlands Police’s “very stretched” budget, with cuts of more than £150 million forecast over five years.

Mr Jones told Ms May: “I have previously written expressing my disappointment at the decision to move from full recovery of policing costs for party conferences, to the police only being able to reclaim 85 per cent of such costs.

“In the case of the forthcoming Conservative Party conference in September in Birmingham this will add approximately £500,000 of costs to the police budget at a time of deep cuts.”

Mr Jones also asked for reassurances the force would be reimbursed in full if it was forced to spend more money replacing private firms which were currently due to contribute to security.

He insisted his demand was not an “abstract question” – and cited the shambles surrounding G4S and the London Olympics.

The company was unable to carry out the work it had been contracted to do and police forces had to be drafted in instead.

Labour MPs have already criticised the cost of the Tory conference after it emerged that more than 95 per cent of Birmingham’s major events budget was being spent on it.

The city council is spending £1.48 million, leaving just £67,000 for other events.

But investment body Marketing Birmingham has claimed the conference could generate up to £20 million for the region’s economy.

Labour MP Jack Dromey (Lab Erdington), Shadow Minister for Policing, said: “Theresa May first slashes the West Midlands Police budget and then asks them to shell out half a million pounds to guard the Tory Party conference.”