Extreme sports star Alexander Polli has died after crashing head first into a tree during a jump in the French Alps on Tuesday (23 August). Polli was killed just after 11am local time at the Couloir Ensa, near Chamonix, France.

Emergency services were called but Polli, 31, reportedly died at the scene. A spokesman for PGHM mountain rescue in Chamonix - who wished only to be identified as Mercer - told NBC News that Couloir Ensa was popular but dangerous. "It's a location where there are a lot of accidents," said Mercer.

Italian-Norwegian national Polli was one of the most famous skydivers on earth, his stunts including the 2013 "Batman Cave" jump in Montserrat, Spain when he dropped from a helicopter and flew through a small hole in the side of a mountain at 155mph (250kph).

Footage of the jump had been seen 13 million times on YouTube and the Base-Jumping EU blog wrote: "This extraordinary flight exceeds the level of commitment most fliers would ever consider—there can be no attempting, the only option is success!"

In an interview with Deutshe Welle newspaper in 2013, Polli admitted dying scared him. "To be quite honest: I am extremely scared of dying - and I am scared of heights," he said. "I never would have embarked on this kind of sport if I had had to be the first to do it.

But in fact there were other parachutists, skydivers and BASE jumpers who'd been doing this for 20 years. So I just asked myself why can they do that and I can't? Is there something I really can't do or is it simply fear that is stopping me?"

BASE jumping and wingsuit flying are two of the most dangerous extreme sports, with a number of fatalities in recent weeks. These include Uli Emanuele, 29, who tragically filmed his own death while attempting a stunt in the Swiss Alps and a Briton and an Italian who died, also in the Swiss Alps on 18 August.

Mark Sutton, who famously parachuted into the 2012 Olympic Games opening ceremony in London, died in 2013 when he crashed into a mountain.