Hundreds of staff at the Royal Courts of Justice and London School of Economics were evacuated again today after a building due to be demolished collapsed 'like a pancake' injuring a 56-year-old workman. Workers underneath the six-storey structure fled for their lives after the fifth, fourth and third floors crashed down on to the rest of the building - sending a huge cloud of dust into the air. The terrifying incident is just yards from where an underground cable fire ripped through Holborn on April 1 bringing parts of central London to a standstill and costing local firms £40million. Scroll down for video . Building collapse: Hundreds of staff at the Royal Courts of Justice and London School of Economics were evacuated again today after a six-storey structure collapsed . Injury: Police said a 56-year-old man was being treated for injuries this afternoon following the disaster . Staff at both LSE and the Royal Courts of Justice were also evacuated on that occasion and at this stage it is unknown whether the two incidents are related. The collapsed building, located just behind the university, was covered in scaffolding when disaster struck shortly after 4pm this afternoon. Students at LSE were seen evacuating the university's library and have been told to 'stay clear' of the area. One worker suffered head injuries and a broken arm and was treated by colleagues trained in first aid until an ambulance arrived. Two incidents in a matter of weeks: A map shows where the building collapsed today - not far from the underground cable fire that tore through Holborn on April 1 costing local firms an estimated £40million . An air ambulance was seen arriving at the scene this evening and a 56-year-old was taken to hospital with head injuries . He was the only casualty among 30 workers on site at the time. Nathan Kennedy, 28, was working in the site office when the building behind the Royal Court of Justice and LSE began to collapse. He said: 'We are used to big bangs and crashes all the time, that's the nature of demolition. 'I was just finishing off some paperwork when there was a huge crash and a rumble, we knew it was out of the ordinary and everyone ran outside. 'We are trained for this so everyone kept calm, but it was the first time anything like this has happened to me. 'There was a huge dust ball, we were checking everyone was all right when a couple of the first aiders brought out one of the guys. Parts of scaffolding spill over the barrier around the site and a construction vehicle could also be seen among the piles of rubble . The building, located directly behind LSE, is just yards from where the underground cable fire started at the beginning of April, bringing parts of central London to a standstill . 'He had a bad cut on his forehead and I think he could have broken his arm. We are all worried for him, he's called Keiran and he's in his 50s or 60s. 'Everyone is shaken up, we just hope he's all right.' A London Air Ambulance helicopter landed in nearby Lincoln's Inn Fields to pick up the injured man. Workmen have been on site for around five months and demolition was in progress when the collapse occurred. Mr Kennedy added: 'There a stretch around 15 to 20m that's collapsed. We've been here since December, the building was seven floors and we've gone down three. 'There's some heavy machinery on the higher floors, we use a machine called a muncher that chews through the walls, it's like a big claw, that may have fallen down. 'There's been a lot of building work around here but this is far enough away I would be surprised if that had anything to do it.' Speaking at the scene London Fire Brigade station manager John Snelgrove said: 'We have one waking wounded who has been taken to hospital and we are unaware of his condition. A cloud of dust hovers in the air following the building collapse in Holborn, central London . Fire crews attend the scene on Portugal Street, near the London School of Economics, today . People in the vicinity reported feeling the ground shake as part of the huge building collapsed into rubble . 'The collapse is known as a pancake and has taken around third to two thirds of one of the sides down with it. 'Fortuitously the collapse has largely stayed within the site and not hurt any passers by. 'This is a busy area, luckily the building collapsed inwardly, although a few cars were damaged by fallen masonry.' Scotland Yard said: 'We were called at 4.14pm to Portugal Street, Aldwych, following reports of a partial building collapse on a building site. 'Officers, London Ambulance service and London Fiere Brigade are in attendance. One male aged 56 is being treated at the scene. The Health and Safety Executive has been informed and road closures are currently in place.' A London Fire Brigade spokesman said: 'One hundred people were evacuated from the building site and a further 100 people were evacuated from nearby properties. A safety cordon is in place.' The London School of Economics (LSE) Students' Union's Twitter account tweeted a picture of the scene and said it was 'just by' the LSE campus. And LSE assistant professor Bryan Roberts tweeted: 'Building just collapsed next to my office at LSE in Holborn. When the structure came down there were 30 men working on the site - luckily just one was injured . Students at the London School of Economics have been evacuated and told to 'stay clear' of the area . 'Some workers hurt. Shook the whole campus. Ambulances just arrived at LSE where the building fell down. It's the old London School of Business building.' Eyewitness Murat Akkulak, a research co-ordinator at the Royal College of Surgeons, told the BBC: 'There was a lot of dust but I could see there was a digger down amongst the rubble and one or two builders were running around trying to get someone out of the digger. 'They seem to have had a really lucky escape to me, because everything else had just collapsed around them.' The incident comes just weeks after a fire on nearby Kingsway, which was caused by faulty electrical cables underground, sending thick clouds of smoke into the air - engulfing buildings. Dramatic photographs from the scene showed crowds of people on the street as power cuts hit office buildings. Onlookers reported 'struggling to breathe' while later that night some 5,000 homes and businesses in central London were left without electricity following a huge power cut. Phone lines went down, thousands of workers fled their offices while West End shows including The Lion King, Charlie and the Chocolate Factory and The Play That Goes Wrong were all cancelled. Fire earlier this month: The fire on April 1 was said to have been caused by faulty electrical cables underground, sending thick clouds of smoke into the air - engulfing buildings . Dramatic photographs from the scene showed crowds of people on the street as power cuts hit office buildings . Onlookers reported 'struggling to breathe' while later that night some 5,000 homes and businesses in central London were left without electricity following a huge power cut . Around ten days ago, a former commander of the Metropolitan Police's elite Flying Squad has said the Hatton Garden gem heist could be linked to the fire. Speaking on LBC, John O'Connor, a highly experienced former police detective, said: 'I've never heard of an outage of electricity like that causing a fire that lasted as long as that. That seems to me as too much of a coincidence.' He also said that in his opinion, to succeed with such a complicated and ambitious crime, the gang must have had some inside help.
Six-storey structure collapsed this afternoon in Holborn, central London .
Site is just yards from where cable fire caused chaos earlier this month .
On both occasions university and court staff have had to be evacuated .
Not yet known whether today's incident is connected to underground blaze .