Westminster was London Air Ambulance's busiest borough last year with call-outs to 120 patients.
London’s Air Ambulance (LAA), the charity that delivers an advanced trauma team to critically injured people in London, treated 1,806 patients in 2014. But the busiest borough was Westminster.
Mark Field, MP for City of London and Westminster, said: "Last year, 221 critically injured people were treated in and around my constituency and it is an enormous comfort to every person visiting, working and living in central London to know that there is a team of medical experts in the sky, ready to protect us in our time of greatest need."
Mr Field supports the air ambulance's Your London, Your Helicopter campaign to raise money for a second helicopter by this summer.
He added: "It would be fantastic if we could see this incredible service expanded by getting a second helicopter, allowing more patients to receive the kind of care and emergency support that can really prove to be the difference between life and death."
Charles Newitt, LAA's chief operating officer, said: "While Westminster was our busiest area in 2014, there are any number of factors that could attribute to this. Density of population, weather or events to name a few."
He added: "Traumatic injury can sadly happen to anyone, anywhere at any time. By having a second helicopter available to us, we can ensure our advanced trauma doctor and paramedic are always by a critically injured person’s side in the quickest possible time."
Elsewhere, there were 82 incidents Hillingdon to which the air ambulance attended, and 67 in Ealing, 55 in Brent, 38 in Hammersmith & Fulham, and 32 in Harrow.
Virendra Sharma, MP for Ealing North, said: "LAA is the emergency service that London deserves. Having treated more than fifty people in Ealing and Southall, who may otherwise have been unreachable, the air ambulance has changed hundreds of lives."
The most common reason for treatment was due to road traffic collisions, causing a third of all helicopter missions.
The statistics show nearly a quarter of call-outs were the result of violence, with stabbings and shootings accounting for 24%, while falls accounted for 27% of calls and 16% were categorised as ‘other’ , including incidents on rail networks, hangings and drownings.
John McDonnell, MP for Hayes and Harlington, said: "In west London our roads can easily become gridlocked and so the ability to call upon the air ambulance can mean the difference between life and death. That's why a second helicopter is vitally needed."
A total of £6m is needed to purchase the second helicopter and extend its daylight flying hours for five years.
The freemasons pledged £2m towards the campaign but another £2.35m is still needed to reach the target.
London residents are being urged to donate as £50,000 has already been raised by the public.
Graham Hodgkin, LAA CEO, said: In Westminster there is a population of 219,600. If all those people were able to donate just £5 we would be £1,098,000 closer to getting the second helicopter in the air.”
To donate, text SAVE to 70800 to donate £5 or visit yourhelicopter.london for more details.