Devon and Cornwall Police are to lose 700 officers in the wake of the government's Spending Review, the force's chief constable has said.
Spending on the police is to fall by 4% a year for four years, Chancellor George Osborne announced.
Chief Constable Stephen Otter said that the loss of officers would be through retirements and because a recruitment freeze was in place.
He added that everything was being done to maintain the visibility of officers.
Mr Otter said the planned budget cuts would result in a total shortfall of about £40m over the four years.
He said that it meant that the force - which has about 3,500 officers and another 3,000 civilian staff - was predicting losing about 1,000 people.
Mr Otter said that there was "no doubt" that officer numbers would have to decrease, but that the force was preparing for the cuts by coming up with ways of working differently to protect services.
He said: "We're changing the way we work completely.
"Officers who are available for emergency calls are to be protected and we're prioritising what the public say are their priorities, not just in terms of emergencies, but for things locally that they say are a priority.
"These are things around anti-social behaviour, local visible policing, and we're prioritising around protecting vulnerable people from harm, which is often invisible from the public eye."
He added that the force had also made "significant reductions" in its back office costs.
Nigel Rabbitts of the Police Federation, which represents rank-and-file officers, said any cuts would affect services.
He said: "We must maintain this gold-standard service the public expects.
"They will be betrayed if the number of officers falls below 3,500."
In June, the Devon and Cornwall Police Authority said that more than 180 police officers were expected to be shed in a bid to meet government cuts after it was told to cut £2.8m in this financial year's budget.