'Keep air ambulance flying or Londoners will die'

The service, which relies on charitable donations, has a £55,000 annual bill for petrol. Its total annual running costs are £2 million.

Andrew Cameron, chief executive of London's Air Ambulance charity, said: "With the cost of fuel having a direct effect on our service we need to rely more than ever on the generous donations of our loyal supporters in order to stay operational."

Last year the Air Ambulance was called out to 1,400 emergencies including 176 stabbings and 33 shootings. Supporters say Londoners' lives will be put at risk if the number of call-outs is restricted.

The new fundraising appeal comes after a £100,000 donation by a reader, in response to an Evening Standard appeal, helped the ambulance launch a 24-hour service in January. Previously it did not have enough funds to operate at night.

A spokeswoman said: "The donor read the Evening Standard article and added the London Air Ambulance into his will. He sadly died a few months later but his money has made an amazing difference to the service."

The NHS pays the wages of the doctors who work on the ambulance, at a cost of £980,000 each year, and Virgin donates £190,000 every year. The rest of the money - £850,000 - comes from fundraising.

Met police officer Ian Grant is backing the campaign. The air ambulance saved his life in 2006 after he was involved in a motorbike accident in which he was crushed under the wheels of a 40-tonne lorry on the M1.

The 43-year-old road traffic officer from Luton said: "If it wasn't for the air ambulance crew I would have been dead. I was dragged underneath the wheel of a lorry and my stomach, bowels and bladder were ripped open.

"I broke my back, pelvis, eight ribs, kneecap, elbow and both my lungs collapsed. The doctors were able to operate on me while I was lying in the road. The accident happened in the morning rush hour but it only took the helicopter 13 minutes to reach me.

"It is ludicrous that so much money has to come from donations. It is an air ambulance for all Londoners. If it cannot fly lives will be needlessly lost. If everybody could give £1 each it would be great."