London's Air Ambulance Charity is aiming to raise £15 million to replace its two helicopters and continue to save lives across the capital.

The charity, which operates from the top of The Royal London Hospital, said it needs to raise the money by 2024 to replace both its aircraft, which are becoming increasingly difficult to maintain.

The new campaign, Up Against Time, launched today (Tuesday, October 4) with volunteers, staff and off-duty crew from across the organisation collecting donations on the streets of London throughout the morning.

The charity is also looking to raise awareness by publishing new polling data as part of the campaign launch with research finding that only 38 per cent of Londoners know the service is primarily funded by public donations.

Just over a third – 36pc – said they think the service is funded by the NHS or central government.

London's Air Ambulance Charity said it found that 51pc believe the main purpose of its helicopters is to collect patients from the scene of an accident and take them to hospital.

But the organisation said its role includes getting medics to the scene quickly so they can provide complex treatment to critically injured patients with life-threatening or life-changing injuries, who do not have time to make it back to hospital.

The survey found that 33pc of respondents do not know that air ambulance medics carry out procedures such as open chest surgery, blood transfusions and reinflating collapsed lungs at the scene.

Last year, the charity assisted 1,714 patients at the scene – an average of five a day.

Dr Tom Hurst, medical director, said: “When patients are so seriously injured there is no time to reach hospital, our medics give life-saving treatment at the scene – like open chest surgery and blood transfusions.

“But we’re a charity, and without public support we wouldn’t be able to reach our patients in time to help them.

“Right now, we have an urgent need to replace our helicopter fleet – the current helicopters are becoming increasingly difficult to maintain.

“It’s only with the backing of the public that we can continue to serve all those who live and work in London when they need us most.”

Those wishing to donate can do so at fundraising.londonsairambulance.org.uk/event/big-city-collection