London from the sky: Flying high with the air ambulance
London's skyline has been transformed in recent decades - with the Shard, the Walkie Talkie and the Gherkin now among the capital's iconic skyscrapers. The pilots of London's Air Ambulance service have witnessed that change. As the charity marks its 25th anniversary, BBC News took to the skies to get a pilot's eye view of the ever-changing city beneath.
Attempting to commute the 15 miles (24km) from Northolt, west London, to east London's Whitechapel in the morning rush hour in anything less than an hour may sound ambitious. But Pete Driver and Johnny Crewsdon manage it most mornings in less than 10 minutes.
The flight from London Air Ambulance's storage hangar at RAF Northolt to the helipad on top of the Royal London Hospital takes them over a much-changed skyline.
"London from the skies is a very different picture today than it was a decade ago," says Mr Driver. "There are a lot more buildings that pierce through the low lying cloud."
"It's been fascinating to watch the Walkie Talkie take shape," he says of London skyline's latest addition - 20 Fenchurch Street, nicknamed the Walkie-Talkie, because of its distinctive look.
"I've flown in and out of most cities in the world," adds Mr Driver. "London can compete with any of them but it isn't just the manmade structures that defines a city from the air.
"The River Thames is a significant geographical reference for London."
London's famous tall buildings
- The Shard, 306m (1,004ft). At 87-storeys it's the tallest building in the European Union and was completed in 2012
- One Canada Square, 235m (771ft). The tallest building in Canary Wharf, completed in 1991
- 30 St Mary Axe, 180m (590ft). Nicknamed the Gherkin, it's not the tallest building in the City of London but probably the most distinctive
- BT Tower, 177m (581ft). The tallest building completed in London in the 1960s, sitting proudly in Fitzrovia
- 20 Fenchurch Street, 160 m (525 ft). Aka the Walkie-Talkie, it was nicknamed the Walkie-Scorchie in 2013 when sun rays reflecting from the skyscraper melted parts of a Jaguar
As the capital has become more built-up, finding a landing-spot has become more of a challenge.
"Before you could always find a green space to land, but now everywhere is getting built on," Mr Crewsdon says.
Fortunately the helicopter only needs to find a spot the size of a tennis court - even busy places such as Oxford Circus or the British Museum forecourt are regular landing spots.
Each morning the team has a daily briefing, running through the weather forecast, major road closures and any new obstacles that may have appeared on the skyline.
New cranes are a constant hazard. Mr Driver says he prefers the "classic architecture" of St Paul's Cathedral to the modern skyscrapers springing up in the city because "St Paul's is not very high so is one less building to try and avoid."
But there is often not much time to admire the city's skyline in a job like this.
As we are with the team, a report comes in of a stabbing in north-east London and the crew move quickly to respond.
"We aim to get the aircraft off the ground in three minutes," says Dr Gareth Grier, a senior consultant. "We bring the hospital to the street, be it intensive care or open heart surgery."
Their speedy response is believed to have saved countless lives in the capital.
For instance, in March 2011, the air ambulance was called to Brixton, south London, where a five-year-old girl had been shot in the chest. Thusha Kamaleswaran had been playing in her uncle's shop when she was caught in the crossfire of a gang shooting.
The air ambulance's surgeons operated on Thusha in the street, which kept her breathing until she reached hospital.
London's Air Ambulance
- Serves a population of 10 million people
- More than 31,000 patients have been treated since the service was set up
- The medical team includes four permanent consultants, plus six doctors and nine paramedics who deliver advanced trauma care over a 24-hour shift pattern
- Overnight, when the helicopter does not operate, the team travels in a rapid response vehicle
- London Ambulance Service receives about 5,000 calls a day, with London's Air Ambulance attending the six or seven most serious incidents
- The helicopter carries harnesses, stab vests, a box of blood for transfusions, and bubble wrap which has proven invaluable to keep patients warm
While shootings may make the headlines, it is road traffic accidents that are the most common reason for a call-out, followed by people falling from a height of more than two storeys, and then stabbings, says Dr Grier.
The charity is now raising money for a second helicopter.
"The statistics don't measure the number of people we've saved," he says. "What we've done has without a doubt helped keep those figures lower."
He recalls a recent incident involving a young man who had been stabbed. "The patient we visited was going to die. He'd had a full cardiac arrest," he says. "But we sewed him up, gave him first aid and got him to the hospital.
"If we didn't treat him, someone would have been done for murder."