William Hill chased the culprit out of Costcutter store and down the street, before knocking him to the ground with the help of a passer-by.
The 62-year-old managed to stamp the knife out of the thief’s hand and pin him to the pavement until police arrived.
The father-of-two has been honoured with a [email protected] award from the Scottish Government this week for his actions outside his store in Main Street, Whitburn, in August 2009.
The awards replace the First Minister’s Commendation for Meritorious Conduct, which celebrate courage and bravery of both citizens and emergency service personnel.
Mr Hill told the Evening News: “There was a big queue of people, including my wife.
“This guy came in and bought two bottles of vodka and 40 cigarettes. Instead of money he produced a knife and presented it to Betty. She screamed like it was going out of fashion. I ran after him and shouted to a guy passing who managed to stop him.”
Although the suspect was still holding a knife, the pair wrestled him to the ground.
William, whose son is an officer with the Metropolitan Police, went on: “I stamped on his hand so he let go of the knife. The guy got his bottom half and I put my knee on his top half. The police were only three minutes or so and were delighted we held on to him.”
He added: “Basically, he’d stolen from me, so I just went after him. I never really thought about it at the time.”
Other recipients of the [email protected] award include Aaron Love, 16, from Livingston and Leah Grant, nine, from Linlithgow.
Aaron was just 15 when he jumped into a stretch of water to help two young children whose friends were in difficulty, and managed to pull them to safety in May last year.
Leah was just seven when her mum suffered a seizure. The youngster had learned what to do if a parent falls ill from Children In Need the week before and checked her mum’s breathing before calmly dialling 999.
Paramedics arrived quickly and her mum recovered.
Another award-winner was David Morton, 38, from Livingston, who ran to the aid of a police officer being attacked, and Strathclyde Police Constable Graeme Henderson, 38, who ran into a burning building to rescue a woman and her young family.
First Minister Alex Salmond said: “The [email protected] Awards recognise people who have shown exceptional bravery – people like Leah Grant, Aaron Love, David Morton, William Hill and Graeme Henderson.”