Campbell was identified as the robber from CCTV footage

Steven Campbell, 34, threatened a female member of staff with a nine inch long knife at a petrol station in Glasgow in December last year.

He escaped with �122 but the incident was filmed on CCTV and his fingerprints were found on the cash register.

Judge Lord Mackay said he should also be supervised for a further two years.

The court heard that Campbell walked into the Shell petrol station on Alexandra Parade in Glasgow in the early hours of the morning.

A woman was working on her own and when she asked if she could help Campbell replied: "Aye hen, you can help me. Empty your till."

After he rifled the till he tried to leave the staff area and get back to the public part of the premises but could not open a door.

Christmas gifts

Campbell had to jump back over the counter before making his getaway from the shop.

The victim waited about 30 seconds before triggering a panic button and making an emergency call.

Fingerprints were found at cash registers and security film was discovered to contain footage of the incident.

Police officers later identified Campbell as the robber from the CCTV film and forced entry to his house and recovered knives and clothing.

Defence counsel, Gerry Carroll, told the High Court that obtaining gifts for his 11-year-old son appeared to be the motivation behind the offence.

Passing sentence, Lord Mackay told Campbell: "You have pled guilty to a serious charge of assault and robbery, which involved you presenting a knife at a lady in the petrol station in the small hours of the morning."

He said Campbell would have faced a six-year jail sentence, but for his guilty plea.