Taking police officers from the streets of Hertfordshire to support a private contractor in charge of securing the Olympic Games will not affect crime, according to the head of the police authority.

Frontline officers from nine forces including Hertfordshire, Surrey, Thames Valley, Dorset and Greater Manchester Police are being drawn on to plug a shortfall of security staff.

The government’s security contractor for the games, G4S, has failed to deliver enough staff, and 3,500 soldiers are being called up to help out.

Hertfordshire Constabulary is yet to go into details about how many of its officers are being seconded to the games and what they will be doing.

David Lloyd, chairman of Hertfordshire Police Authority, said: "Hertfordshire police will be working in Broxbourne during the Olympics but the G4S shortfall will be made up by the armed forces."

Mr Lloyd said he didn't know how many officers would be working in central London during the games.

He added: "If you pay for a service it is right to know how it is discharged but people don't need to know how many officers will be on or off the street.

"If someone calls 999 they need to know they will have a response. It is not the case that there will not be sufficient numbers of police on the streets."