National policing lead for finance and resources, Chief Constable Nick Gargan, said:
"If we had to achieve the savings directly by cutting posts then we estimate the size of the police service would reduce by an extra 9,000 people beyond the reductions already predicted.
"We hope to work productively with minsters and officials to achieve these savings in other ways.
"The leadership of the police service will continue to be positive and do its best to implement these cuts and make sure the reductions have as little impact as possible on frontline policing.
"However, successive cuts do have a serious impact on police and if this continues some forces will be left at the limit of their viability within a couple of years."