A Tory MSP who was at the Brighton hotel bombing shortly before the explosion hit told Holyrood of the “long shadow” the attack by the IRA has had on politics.

Jackson Carlaw was among Conservative Party activists at the 1984 party conference, and was drinking in the bar at the Grand Hotel until 1am on the morning of the bombing.

The blast tore apart the hotel where the then prime minister Margaret Thatcher and members of her cabinet had been staying, with five people killed in the explosion and another 34 injured.

Donald MacLean, president of the Scottish Conservatives at the time, was one of those severely injured in the bombing, which took place on October 12 1984, with his wife Muriel among the dead.

Mr Carlaw, speaking in a special debate to mark the 40th anniversary of the attack, described how he had tried to help people “staggering out” of the hotel “covered in soot and dust”.

He described the bombing as an “attempt to wipe out the democratically elected government of the United Kingdom”, adding: “There are some events that you are party to that you never forget.

“And as somebody who was at Brighton the night that bomb exploded, this is one for me.”

He explained he had returned to his accommodation on the night in question, but said he “woke up suddenly with a very deep seated sense of unease that something wasn’t right”.

The Tory told MSPs: “I couldn’t put any finger on what it was, but I felt it.”

He and his companions walked the short distance to the hotel, with Mr Carlaw recalling: “We were 100 yards away from the Grand Hotel and we walked round and there before us was an extraordinary sight.”

Speaking about their efforts to help, he added: “We did what we could, we brought deck chairs up from the beach to help people just to sit down who were staggering out covered in soot and dust.”

Speaking about his “friend” Mr MacLean, he said he and his wife had been staying in room 629 – where the bomb had been placed behind a bath panel.

When it went off “they were catapulted six floors down”, Mr Carlaw said.

“Muriel died a few weeks later from the injuries she sustained, along with four other people.

“Donald was horribly scarred, for the rest of his life he carried the injuries that he suffered that night with tremendous fortitude and courage.”

Mr Carlaw paid tribute to Mrs Thatcher and the “leadership that the prime minister showed the following day” when “everybody was shaken by the enormity of the event”.

But revealing there had been an attack on his office building in recent days, Mr Carlaw said the bombing in Brighton had “led to a change in our politics”.

He stated that before the bombing “you could go to party conferences, politicians mixed and mingled, there was no real security”.

But “from that moment onwards a curtain had come down on the way politicians could engage at the most senior level”, he said.

“And over the years since that has come to affect all of us too.

“I know there are colleagues who have had constituency offices attacked and I can say tonight that last week a woman came to attack my office, she attacked the staff in the shared services area of the building, she was arrested by the police and has been charged.”

Mr Carlaw continued: “These things visit all of us and have changed the colour and the character of politics, they have made it something we all have to be aware of that we never thought we would have to be aware of.

“And that is the long shadow that I think has carried forward from that night in Brighton all those years ago.”