Police chiefs will have to make "very difficult decisions" as cuts bite in the wake of the Olympics, the National Olympic security coordinator said.

Met Assistant Commissioner Chris Allison asked chief constables around the country to delay cutting specialist officers until after the Games.

Forces have been told to cut millions from their budgets and chief constable of West Yorkshire Police Sir Norman Bettison warned last week that any further cutbacks would leave officers unable to cope with a repeat of last year's riots.

It also emerged that Devon and Cornwall Police did not pursue more than 36,000 cases reported to them, representing 40% of all crime files, due to budget cuts.

Mr Allison said: "When the comprehensive spending review was announced a couple of years ago we were told we would have to reduce policing costs by 20% over a four year period.

"Thankfully I've been fantastically supported by my chief constable colleagues up and down the country because I asked them to delay any cuts in specialists until after the Games because I needed those specialists to deliver the Games, and we've been able to deliver what I think has been a fantastic event.

"But those cuts are starting to bite, they're starting to hit the service and nationally chief constables are having to make some very difficult decisions about what they're going to stop doing to ensure that they live within the budget that's now been given to them.

"We're exactly the same in the Met, and very hard and difficult decisions are going to have to be made over the next few weeks and months as we plan for the future."

Scotland Yard has already been told to save more than £500 million, and last month the outgoing Chief Inspector of Constabulary Sir Denis O'Connor warned it still had to plug a £233 million hole. The Olympics was the Met's biggest peace time operation, with more than 14,000 officers on duty on peak days, drawn from 52 different forces.

Scotland Yard now has a two-week transition period, before dealing with what would normally be its biggest annual event, Notting Hill Carnival. Two days later, the Paralympics starts, with 6,000 to 7,000 officers working each day.

The Press Association, photo by Panasonic UK