A skyscraper climber, dubbed the French Spiderman, has struck again – this time at one of London’s tallest buildings.

Alain Robert, whose whose feats have included climbing Dubai’s 2,717 foot-tall Burj Khalifa, is tackling the Heron Tower in the City of London.

The 56-year-old daredevil, who is known for scaling skyscrapers with his bare hands, said before his climb: “I fully feel alive when my life is at stake. It may sound a bit scary and crazy but this is the way it is.”

The illegal ascent of the 662ft (202m) tower – now known as the Salesforce Tower – is with no safety gear, without a rope and with bare hands.

Uniformed City of London Police officers arrived at 1.37pm, set up a taped cordon stopping traffic around the building and ushered the growing crowd to move back and keep out of the road.

Robert is in prime condition – he is 5ft 5in and weighs about 7st 12lb (50kg), with a low fat ratio of bones to muscle which helps his extreme athleticism and skill.

As with other unlawful climbs, he is as “always” carrying his passport in a chalk bag “because it is very reassuring for the authorities” when he is arrested.

Chalk slightly improves the friction between his skin and the building but he also tapes his fingers and wears wafer-thin gloves to try to stop them being shredded by the “aggressive” building.

It is believed he only decided which building he was going to tackle from a three-strong shortlist on Monday.

He said: “I saw it. I touched it a bit. I tried it just a tiny bit.

“I am not really knowing much. It is only really when I start climbing that I know. I need to feel it.

“There has been 44 years in which I have been climbing. This is what I know as a way of living and expressing myself and living my dreams, my passion and living my life as fully as I can.

“Definitely it it dangerous. I have a certain knowledge. I have a solid background.”

None of this is easy for his family and there are many members of the public worldwide who condemn him.

He said: “It is never easy for family having a dad who is doing that kind of stuff but they are used to it. They never asked me to change my lifestyle.

“They trust me. They think I am capable to succeed each time I am doing something, but at the end of the day it is still a bit scary for sure. They are proud.”

“If you knew the number of people who are happy to meet me.

“For most of the people I am an inspiring person. I am receiving a lot of messages saying I am such a legend.

“There are a number of people who really think that what I am doing is crazy but in a nice way. I am really inspiring a generation.”

The talented rock climber turned his attention to skyscrapers in the mid-1990s and has now done up to 160 of these ascents to date, according to his manager.

Landmarks tackled include the Taiwan’s Taipei 101 and the Lloyds building in London.

Asked if what Robert was doing was actually a little barmy and just plain dangerous rather than a daring adventure, his manager, Bryan Yeubrey, said: “I just have to accept that. I can not argue against it, can I?

“Alain is an adventurer. He wants to climb buildings. He is incredible. He is good at it and has been doing it for many years.”