Ms Deacon was in the office at the time

The Labour MSP was inside her Portobello surgery in Edinburgh when an attacker smashed the windows.

She said the incident had sent a shiver down her spine.

Westminster MP Gavin Strang, local councillor Maureen Child and several members of staff were also inside the building.

A man approached the building, pulled out what appeared to be a sledgehammer and shattered three plate glass windows before running off.

'Very frightening'

The office was showered with glass, but no-one was injured.

The incident happened on Friday morning but details have only just come to light.

Ms Deacon said: "It was very frightening but with any incident like that the shock only kicks in after the event.

"I certainly hope that neither I nor my colleagues or staff have to go through anything like that ever again."

It all happened so quickly we really didn't have time to think about anything other than our own safety Susan Deacon

She said they were having a meeting when they heard a crashing noise and shouting from the shop next door.

They then saw a man approach the constituency office and smash the windows with a small sledgehammer before running off towards Bridge Street.

Ms Deacon said: "We instinctively ran to the back of the office because the glass was everywhere and we rushed into an office and phoned the police.

"We didn't think it was advisable to run out and pursue a man wielding a large implement.

"At the time it all happened so quickly we really didn't have time to think about anything other than our own safety. It's afterwards that a shiver runs down your spine about what could have happened."

Toughened glass

She said she was relieved no-one was hurt in the incident.

"We don't have any idea at all why this happened," she added.

"None of us knew him. But it would be unwise to speculate about the motive at this point."

Ms Deacon said toughened glass had been fitted and that she and her staff would consider the need for any further safety measures.

Toughened glass has been installed at the office

Police said the man involved was white, in his late 30s, and of slim to medium build.

He had short, dark, wavy hair and an "unshaven scruffy appearance" and was wearing a dark jacket, beige trousers and dark top.

A police spokeswoman said: "It is vandalism. I don't know if he had some kind of agenda with the Labour Party or if he's a disgruntled constituent.

"Nothing was said. He just came and attacked the windows and ran off."

A Labour Party spokeswoman said there were no plans to toughen up safety in constituency offices despite the attack.