Horrifying moment masked raider threatens Co-op shop worker with a SPEAR GUN Nikolas McGregor held-up a store in North Lanarkshire Shoppers fled in terror as the 24-year-old armed himself But McGregor fled empty handed when a security guard challenged him A masked robber has been jailed after being caught on CCTV threatening a terrified shop worker with a spear gun. Nikolas McGregor demanded cash from Patricia Murphy during a hold-up at a busy Co-Op store in Hamilton, North Lanarkshire. Shoppers fled in terror as the 24-year-old armed himself with the weapon - normally used to kill fish. Raid: Nikolas McGregor (pictured) holding up the Co-operative store in Hamilton, North Lanarkshire, with a spear gun But McGregor fled empty handed when a brave security guard challenged him and police later caught him hiding in a garden. McGregor was locked up for four years and two months at the High Court in Glasgow after he admitted to a charge of attempted robbery. A judge told him he had been involved in a 'distressing and frightening' incident. CCTV footage played in court showed McGregor strolling into the Co-Op in Mill Road, Hamilton, on August 17 this year. His face was covered with a wooly balaclava and he wore a bright red tracksuit and a flourescent builder's vest. McGregor soon brandished the spear gun at worker Miss Murphy and told her: 'Open the f****** till or I will use this.' McGregor running into the story. He was sentenced at the High Court in Glasgow to four years and two months Some customers raced out of the store while Miss Murphy could be seen crying as she cowered behind the till. Security guard William Russell challenged McGregor, who threatened to shoot him before trying to strike him with a vodka bottle. McGregor eventually ran out before police - including a firearms unit - went on the hunt to find him. He was discovered that day hiding in a garden swigging from a can of beer - claiming he was waiting for his girlfriend. The spear gun and clothes he had worn during the raid were found in a nearby bin. It emerged the weapon was not in working order and could not fire although staff at the Co-Op did not know that. The court heard a traumatised Miss Murphy only returned to work last month. Gerry Considine, defending, said drug dealers had threatened to kill McGregor the day before the raid due a debt that he had built up. Mr Considine said McGregor, of Scotstoun, Glasgow, then 'foolishly' decided to rob the shop to get cash. Lord Bannatyne told McGregor: 'This serious offence involved the use of a spear gun - the fact it could not be fired makes no difference. This was a very distressing and frightening experience (for Miss Murphy) and this has had a very significant effect on her.