[4] Using a helicopter from 08:00 to sunset and rapid response vehicles by night, the service performs advanced medical interventions at the scene of the incident in life-threatening, time-critical situations.

The charity was the first in the UK to carry a senior doctor in addition to a paramedic at all times on a helicopter, introducing a system that reduces the death rate in severe trauma by 30–40%.

Missions commonly involve serious road traffic collisions, falls from height, stabbings and shootings, industrial accidents and incidents on the rail network.

The team can perform advanced life-saving medical interventions, including open heart surgery, blood transfusion and anaesthesia, at the scene.

The service has adopted elements of medical, military and aviation culture to deliver the highest standards in intensive care to the roadside.

From 6 March 2012, the helicopter became the UK's first air ambulance to carry emergency blood supplies, allowing transfusions to be administered at the scene of an accident rather than later in hospital.

[17] A specialised refrigerator installed in the helicopter allows the transport of four units of the universal O-negative blood type which can be stored in the aircraft for up to 72 hours (unused stocks can be returned to the hospital).

The United Kingdom Government contributed £1M using funds obtained from fines imposed on banks,[20] with the remaining £1M being raised by public subscription.

[21] In addition to the standard livery, it bears the masonic Square and Compasses symbol on each side, with the words "London Freemasons" lettered under the doors, to reflect the significant funding from the organisation.

[2][24] At night, or when the helicopters are offline the medical crew still respond to emergencies, but travel in specially equipped rapid response cars.

[citation needed] They are noticeable from other ambulance vehicles as they are painted in red with high-visibility markings to display their advanced trauma team status.

Barts Health NHS Trust provides the helipad facility at The Royal London Hospital and remunerates the doctors seconded to and consultants permanently associated with the service.

The charity also runs a lottery for £1 a week to raise funds for the service, and holds a number of small and large scale fundraising events throughout the year.

Over the past 29 years, the service has coordinated on-scene medical response to the majority of London's major incidents, including the 7/7 bombings, the Soho nail bombing, the Grenfell Tower fire, the Bishopsgate, Aldwych, Westminster and London Bridge terrorist attacks and Paddington, Cannon Street and Southall rail crashes.

At night or in adverse weather conditions, the same medical crew operate from a rapid response car, which is driven by the paramedic on blue lights and navigated by the doctor.