Tottenham Court Road in London where 1,00 office workers have been evacuated. Photo: Twitter

MORE than 1,000 office workers were evacuated from Tottenham Court Road in London today after a man wearing gas canisters took office workers hostage and threatened to blow himself up.

Tube stations were closed, businesses evacuated and the capital's busiest shopping street shut as armed police laid siege to the central London office just weeks before the Olympics take place.

The suspect, thought to be enraged after failing a HGV training course, was removed from Shropshire House in Tottenham Court Road by police officers who then began searching the building.

The Metropolitan Police said: "We have arrested a man at Tottenham Court Road. A search of the building is under way.

"We are not aware of any hostages at this stage. Search of the building continues on Tottenham Court Road."

The central London street was closed after police received emergency calls at midday.

Scotland Yard sent a hostage negotiator to the scene amid reports that the man was holding people captive inside the building several floors up.

Pictures emerged of computer and office equipment being thrown through one of the office windows.

Abby Baafi, 27, the head of training and operations at Advantage, a company which offers HGV courses, said the man targeted her offices and held four men hostage.

In a YouTube video Ms Baafi said the man, calling himself Michael Green, entered her office.

"I recognised him because he was one of our previous customers but he is not quite stable - mentally stable," she said.

"He turned up, strapped up with gasoline cylinders, and threatened to blow up the office.

"He said he doesn't care about his life.

"He doesn't care about anything, he is going to blow up everybody.

"He was specifically looking for me but I said 'My name's not Abby' and he let me go."

Ms Baafi said the man failed the HGV training course and wanted his money back.

The man was named at the scene as Michael Green, 49.

Sarah O'Meara, who also works for the Huffington Post, said they evacuated their offices in nearby Capper Street after being alerted by a woman who ran into the building.

"A woman ran in off the street saying 'There is a guy with a bomb and he is threatening to blow himself up' and that we needed to evacuate," she said.

"Everyone got out."

John Lillis, a consultant at furniture shop Designer Sofas, witnessed the incident unfold from the back of his showroom.

He said: "The buses had been stopped and there was an ambulance crew there, as well as police cars. The road was then cordoned off.

"The police asked us to move to the back of the showroom.

"I looked across the road to an office block opposite our showroom, and I saw computer screens and computers come out of the window, and then a filing cabinet.

"About half an hour after it all started, we were asked to move behind the cordon on Goodge Street, and it has moved back further since then."

Asked if he could see who was throwing the items out on to the street, he said: "All I saw was someone in a shirt, I couldn't see him or her."

Rajesh Kalia, of Goodge Law solicitors, who works two floors below where the incident was unfolding in Shropshire House, said: "We were in the office and suddenly we were told by the police that there was some problem in the building and asked to evacuate immediately.

"The police were very clear about the instructions. There was no panic or anything but they were very firm and got everybody out of the building very, very quickly.

"I overheard someone say that there was a man in there with some wires coming out of his jacket.

"Now, I don't know how much of that is true but that's the impression they gave us.

"They mentioned something about a flame-thrower, the jacket and wires coming out of it, and that's about it.

"We're two floors below where this was happening.

"We heard some shouting in the stairwell and then were asked to leave by the police so I think the police got there pretty quick."

It is not known how the suspect arrived at the scene, whether by vehicle or on foot.