Iain Ferguson was chatting to victim Louise King in an Edinburgh pub after he had been attending a Scotland rugby match at Murrayfield last year.
Ferguson, 53, had bought a signed rugby ball at the stadium and was intending to place it at his son Zak’s grave as a tribute.
But during the couple’s chat about the dead man, Ferguson became increasingly irate and ended up shoving Miss King out the pub door before punching her to the face.
The shocked woman had two front teeth knocked out during the unprovoked attack outside the upmarket Cafe Royal in Edinburgh city centre.
Ferguson’s 18-year-old son Zak was killed in a horror motorcycle accident when his bike collided with a digger on a busy road near to Inverurie on December 9, 2009.
Now Ferguson, from Badenscoth, near Rothienorman in Aberdeenshire, has been ordered to pay Miss King a total of £3,500 in compensation after admitting the “shocking” attack last November.
On Tuesday, Edinburgh Sheriff Court was told Ferguson had been attending the Scotland v Fiji match at BT Murrayfield that afternoon before heading into the city centre for drinks.
The plant fitter ended up in the Cafe Royal bar with a pal at around 8.30pm on November 10 where the pair became “engaged in conversation” with Mrs King and her friend.
Fiscal Nicole Lavelle said during the chat Ferguson told Miss King that “his son had died in a motorcycle accident” but that the pair soon began to argue.
Mrs Lavelle said: “The argument was ongoing and the accused was said to be standing uncomfortably close to Miss King.
“Miss King then stood up and the accused started to push her towards the door of the premises.
“This was noted by an employee who said Miss King was very uncomfortable.
“The two come out of the bar and the accused pushed Miss King up against a wall and stood facing her.”
The bar staff member went outside to check on the pair and the barmaid saw the victim mouthing “For God’s sake someone help me”.
The fiscal added: “She went to get help and as they approached the door the accused has punched Miss King to the face.
“Miss King was found on the ground bleeding heavily from her mouth.”
Photos of Ferguson taken that night were then passed on to police and he was caught ten days later when he handed himself in to his local police station in the North East.
The prosecutor told the court Miss King’s dental treatment to her injuries is likely to cost in excess of £3,000.
The ambulance worker, who is in her 50s, was also forced to take one month off her work due to the injuries she suffered.
Defence solicitor Dan Cameron said Ferguson had been in Edinburgh for the international rugby match and had been drinking throughout the day.
Mr Cameron said: “A conversation was struck up between him and the complainer and he had a signed (rugby) ball that he had purchased that day.
“He bought it as he was planning on putting it at his son’s grave.
“However after the discussion about the ball either through drink or a misunderstanding it caused him to get upset.
“It was a comment made about the ball and his son and it spiralled.”
Mr Cameron added Ferguson’s son had died in a motorbike accident and there had been no prosecution or fatal accident inquiry which had left him with “great sorrow and a lot of pain”.
Sheriff Alison Stirling said: “This was a shocking incident and custody would be very much justified.
“However your last conviction was in 1998 and I think in the public interest a compensation order should be made.”
Ferguson admitted assaulting Louise King by punching her on the head to her severe injury at West Register Street, Edinburgh, on November 10 last year.
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