North Yorkshire police officers, including a permanent armed response unit, have been patrolling the base since September 11, working alongside extra MoD police officers who have been drafted in from around the country.

Mr Willis said more funding should be made available to pay for the extra work, which he says may deplete police presence elsewhere in the Harrogate district.

In a letter, sent this week to Home Secretary David Blunkett, he said: "The cost to date of the operation exceeds £850,000 and is likely to rise over £1m.  With the police budget already severely overstretched as a result of recent disasters, including flooding and the Selby train crash, I am extremely concerned regular police cover may be affected."

"There are a number of other issues surrounding North Yorkshire Police and their budget, and I feel they can only be resolved by going to the source direct," he said.

Deputy Chief Constable of North Yorkshire Police Peter Walker confirmed an extra £850,000 would be needed by the end of the year to provide additional security at Menwith and else in the county.

He confirmed North Yorkshire Police had also contacted the Home Office in respect of the additional costs.

"Everybody recognises we would provide an additional patrol presence after September 11 as a common sense thing to do.  Menwith Hill is a famous and obviously important potential target," he said.

Other measures taken by North Yorkshire police include liaising with minority community leaders around the county and providing additional "reassurance" patrol in areas where American personnel live outside the Menwith Hill base.

Mr Willis also launched a stinging attack on what he claims is "heavy handed" behaviour by MoD police.

"The MoD police are armed to the teeth and I have heard people are appalled at the way these men are being heavy-handed with members of the public," he said.

"There is tension between the local police and the MoD police because of it."

Head of Corporate Communications for the Ministry of Defence Police Mervin Dadd said he absolutely refuted any claim MDP officers had been heavy handed and no complaints had been made.

"I would like to think people would be grateful to have experienced highly trained officers guarding the station," he said.

"Obviously the invasion earlier this year by Greenpeace protesters brought media scrutiny, but officers saw the invaders were peaceful and dealt with the situation accordingly."

Mr Walker said North Yorkshire police worked in close co operation with the MoD police at all levels and he had received no reports of tension between the two.