Bolt part falls off Cheesegrater skyscraper in the City of London Published duration 6 November 2014

media caption 'Cheesegrater' bolts plunge to floor

Part of a large steel bolt has fallen to the ground after breaking off the Cheesegrater skyscraper in London.

No-one was injured but an area around the 47-storey Leadenhall Building in the city has been cordoned off.

It fell from the fifth floor to the ground at the side of the building - another bolt also broke off but was contained within the skyscraper.

It is understood the bolts are about the size of an arm and the piece that fell was about the size of a hand.

image copyright AFP image caption The Cheesegrater skyscraper is the tallest in the City of London

The bolt part fell from the frame of the building to the ground on Tuesday while the other bolt broke off last week.

The building, nicknamed the Cheesegrater because of its distinctive sloped shape, is the tallest in the City of London, standing at 734ft (224m).

image caption Construction of the Cheesegrater was completed earlier in 2014

The frame of the building contains about 3,000 bolts of the type that fell to the ground.

The bolt piece that landed on the ground fell into an area at the side of the building behind a hoarding.

The second bolt broke off on the 19th floor but was contained within the building and did not reach the ground.

British Land said the structure was still open to workers but a full investigation was under way and all remaining bolts were being fully examined.

"There is no risk to the structural integrity of the building," the company said.

"Public safety is our priority so we have taken a number of precautionary measures."

image copyright Getty Images image caption The Walkie Talkie skyscraper reflected the sun's rays, melting parts of a Jaguar car

The investigation is being conducted by contractor Laing O'Rourke and structural engineers Arup.

Neither London Fire Brigade nor City of London Police were called to the scene, but the latter were made aware of the incident.

Construction off the skyscraper was completed earlier in 2014 with contractors now on-site fitting out the building's interior.