Police have committed £5 million to controversial plans to bring in private sector partners – but the money may be wasted because the scheme could be scrapped.

Chris Sims, chief constable of West Midlands Police, told MPs he would have to convince the new police and crime commissioner, to be elected in November, to agree to the deal before it could go ahead.

But he also admitted the force didn’t yet know what any private sector partners would be able to do. Instead he said he was on a “process of discovery”.

Mr Sims was speaking to MPs about plans by the West Midlands and Surrey forces to sign contracts worth a total of £1.5 billion with private sector partners such as security firms.

Critics have attacked the proposals as “privatisation” and 36 MPs have signed a Commons motion warning “privatisation of police services will threaten accountability within the service”.

Mr Sims has insisted private sector staff would not carry out front line duties the public would expect uniformed police officers to perform.

But a contract note sent to potential bidders set out activities they might be asked to deliver, which include: “Investigate crimes, detain suspects, manage incidents ... patrol neighbourhoods ... manage high risk individuals, disrupt criminal networks” and more.

And he struggled to explain exactly what they would be doing when he gave evidence to the Commons Home Affairs Committee alongside Lynne Owens, chief constable of Surrey.

He confirmed £5 million had been allocated to simply trying to sign a deal, with the cost shared between the West Midlands and Surrey forces and the Home Office, which has been supporting private partnership plans.

Mr Sims also confirmed the process may not lead to any agreement being signed.

Committee chairman, MP Keith Vaz, asked him: “At the end of the day you are going to have spent £5 million with the possibility no contracts are going to be signed, is that right?”

Mr Sims replied: “It is a possibility.”

Later, he admitted the police and crime commissioner, to be elected on November 15, would need to be convinced to sign off on the deal.

“We recognise there is a risk that a police and crime commissioner comes in with a completely different mandate and mindset and doesn’t want to do the route that we are going,” Mr Sims said.

“The way I treat it is to look at it as a test. If we can come up with a proposal that is so positive in the impact it has on the people of West Midlands and Surrey, then my question is: why would any Police and Crime Commissioner not want to pursue it on behalf of the public?”