A second air ambulance for London has been purchased, the charity that runs the service has said.
The aircraft should arrive from Qatar this week and be in use by early next year after modifications, a spokeswoman for London's Air Ambulance said.
About £3m was raised for the purchase and conversion costs.
It means when one helicopter is being maintained, London will still be served by a traffic-beating aircraft.
The second emergency medical helicopter - a used MD902 Explorer - was paid for by donations to the Your London, Your Helicopter campaign which aims to raise a target of £6m to keep it flying for five years.
The helicopters will alternate taking an advanced trauma team to critically injured people.
The spokeswoman said last year there was an accumulated total of 55 days when the charity's helicopter could not be used because of maintenance work.
London Air Ambulance boss Graham Hodgkin said it was a "truly exciting development for London and the biggest step-change" in the service resilience in the charity's history.
London's Air Ambulance facts
- Founded in 1989, it has treated more than 30,000 critically injured people
- It serves the 10 million people who live, work and holiday within the M25
- It operates in partnership with Barts Health NHS Trust and London Ambulance Service
- In 2014, it treated 1,806 patients: 33% from road traffic incidents, 27% from falls and 24% from penetrating trauma including stabbings and shootings