Jason Kelly was recognised as a customer of the Ladbrokes chain before carrying out the crime. He passed a betting slip over to a woman employee with the message: "Hand the muny over. Theel be no trouble."

His victim at first thought it was ridiculous, but Kelly, 35, told Kirsten Hillen to give him money from the till. He moved the newspaper in his hand slightly and said: "Give me the money or I'll blow your head off."

The victim was terrified and believed he had a gun, and started giving him banknotes from the till. Kelly pocketed £458 before calmly walking from the bookies, in Renfield Street, in Glasgow.

Police were called and staff told them that they thought they recognised the raider as a regular at pubs in the area.

The victim agreed to go with police to try and spot the perpetrator and while standing in Hope Street, she saw him crossing the road. Kelly was detained and told police: "I've still got the money in my back pocket."

Kelly, from Glasgow, said he had wrapped a plastic bottle in the newspaper before the robbery. He admitted assaulting Ms Hillen, 31, on 23 December, 2006, and presenting a covered object at her and pretending it was a firearm and robbing her.

Graham Robertson, the defence counsel, said it was "a particularly ill-thought out" offence. He said Kelly had been drinking, but was not intoxicated at the time of the crime.

The judge, Lord Hodge, told Kelly at the High Court in Edinburgh that he accepted that it was not a sophisticated crime.

But he added: "You did cause the lady in the shop to believe you had a firearm and caused her not inconsiderable distress."