As a Merchant City dweller I'm more than used to hearing and seeing the Police Scotland helicopter on runs over the city centre.

Never, however, could I have imagined seeing it embedded in the roof of a pub that I have on occasion been known to frequent.

Given the Clutha's proximity to my flat, I was on the scene only minutes after the arrival of the emergency services. Completely by chance, one of the first people I encountered was MP Jim Murphy. He was just finishing a phone call trying to explain the horror that had unfolded in front of him seconds after he had driven past to leave his car in the King Street car park.

Much has been said of Murphy's efforts to help at the scene of Friday night's accident and there is no doubt he did all he could. But if one thing other than the crash site itself sticks in my mind about that terrible night, it was seeing the extent to which he had been affected by what he had witnessed.

As we spoke, his hands were visibly and uncontrollably shaking, his voice fluttering as he gave me his account of seeing at least six people lying injured on the street outside the Clutha and of trying to help the victims. "There are piles of people," he told me. "They was no explosion, it was so strange."

In the short time that I spent with him the tell-tale signs of shock were beginning to become more pronounced. One bystander, recognising the symptoms, offered him chocolate to boost his blood sugar. He accepted this and said it helped.

"She know's what she is doing, just like the emergency services here," said Murphy, who throughout our encounter had consistently praised what he had seen of the fire and rescue workers' efforts.

As for the scene at the Clutha itself, there was still bedlam as the firemen moved around the building. Walking around the entire scene it became clear the extent to which the police had quickly and effectively closed off every alleyway and lane around the Paddy's Market area.

From vantage points on both sides of the Clyde I watched until the early hours of Saturday morning the rescue operation under way.

Outside the Scotia Bar on Stockwell Street, the drinkers had emptied out and stood watching in disbelief.

From near the Clutha the sounds of barking dogs, perhaps part of the specialist search-and-rescue unit on the scene, could be clearly heard.

Along the pavements on the edge of the police cordon my photojournalist colleagues were sitting on the kerbside with laptops transmitting pictures of a tragedy that Scotland will long remember.

Having just returned from assignment on the Lebanon-Syria border, over the last few weeks I have witnessed no shortage of horrors. The last thing I expected was yet more of the same in the city that has been my home for decades. In that time I can't recall a more sombre Glasgow Friday night.