The aircraft came down on The Clutha pub at 10.25pm at a time when the pub was packed with drinkers. The police said a crew of two police officers and a civilian pilot were on board the helicopter. A local band was reported to be playing at the venue.
Jim Murphy, the Labour MP for East Renfrewshire who ran into the pub to help, described the scene as “horrific”. He told the BBC: "I was just a few yards away and I arrived on the scene outside the pub a few seconds after the impact. No-one knew what it was but you saw the pandemonium of the people trying to get out of the pub”.
He added: "As you stood there you could see the helicopter embedded in the roof and sticking out the top of the roof and you knew it was something really serious. People just formed a bit of human chain, side by side with each other, to help pull injured people out”.
Prime Minister David Cameron tweeted: "My thoughts are with everyone affected by the helicopter crash in Glasgow - and the emergency services working tonight."
A police spokesman said: "Police Scotland can confirm that the service helicopter crashed earlier this evening in Glasgow city centre. "A major incident has been declared after the Eurocopter EC135 T2 - with a crew of three consisting of two police officers and a civilian pilot - came down on the roof of a pub in Stockwell Street at 10.25pm”.
He added: "Emergency services responded immediately and remain at the scene at the present time. "Cordons have been put in place to allow the rescue operation to take place. At present Police Scotland is not in a position to confirm any details regarding injuries".