Police chiefs have backed the idea of legislation allowing some of Britain's 43 forces to amalgamate after it emerged budget cuts might leave them with no alternative.
The National Police Chiefs' Council (NPCC) told Sky News police must make "fundamental changes" to save cash.
"Most would agree that fewer forces is the best option, but if the desire is to maintain 43 then forces will need to collaborate more," the NPCC's Chair Sara Thornton said in a statement.
That collaboration process would be "helped by there being a new statutory provision that allows forces that want to work together to amalgamate," she said.
The Association of Police and Crime Commissioners estimates that up to £300m could be saved within a few years if forces collaborate in the purchase of equipment.
Nottinghamshire Constabulary is one force leading the way in co-operation with some of its neighbours in the East Midlands.
The force, which has a strength of just over 2,000 officers, has begun sharing some specialist services with Northamptonshire and Derbyshire police.
Ronnie Adams, commercial director of the East Midlands Strategic Commercial Unit (EMSCU), said the culture of different equipment for different forces needed to be addressed if chief constables were serious about driving through more efficient practices.
"When I came to join the police, one of the things I couldn't understand was that there were 43 police forces in England and Wales and those 43 police forces have got 43 different uniforms," he said.
"It's crazy. I can understand why it's happened. It's happened over a period of time.
"But it's been driven because forces have been looking after their uniforms locally. Therefore, there's no need to do something nationally. It needs to get sorted out. Really, we just need to have a single specification of police uniform."
Police forces in England and Wales currently spend around £1.7bn on equipment annually - 13% of their total budget.
But the price for similar pieces of equipment can vary considerably. For standard issue handcuffs, the cost can range from £14 to £43.
The disparity is even wider when you look at police issue boots - from £25 to £114. And high-visibility jackets also vary widely, from £20 to £100.
Nottinghamshire's Police and Crime Commissioner Paddy Tipping is part of a nationwide steering group which has examined ways in which forces can co-operate more closely.
It concluded that potential savings of £300m could be achieved through greater co-ordination on procurement.
"Forces know they have got to do it. Chief Constables who like to be, dare I say it, barons in their own kingdom, know that they want to protect the local policing and the penny has dropped."
While backing the proposed collaboration measures, the NPCC, which was formerly known as the Association of Chief Police Officers (ACPO), warned they may not be enough to help forces deal with the budget cuts.
The NPCC's Chair Sara Thornton said: "We've dealt with cuts of 25% in Government grant in the last five years and are set for similar following the Comprehensive Spending Review in the Autumn.
"We're likely to have lost around 70,000 police posts by 2020. This means we have to make fundamental changes to the way we police otherwise we will fail in our service to the public and unacceptably stress our staff.
"Improving the way we procure equipment and services will save us some money, as will sharing more within and outside policing.
"But they won't solve the problem alone."