AN armed robber trapped inside a ­jewellers by a shopkeeper before ­smashing his way out with a hammer has been jailed.

Leon Caine, 23, of Brixton, South ­London, escaped with a £15,000 Cartier Santos watch in a knifepoint raid on Goldstraw ­Goldsmiths, St Neots, on January 22.

On Friday, he was convicted of robbery after a five-day trial at Peterborough Crown Court.

He was also found guilty of attempted ­robbery following a failed attempt to steal from the Market Square jewellers on ­January 7.

The jury heard how Caine had walked into the shop wearing a mask and threatened Jack Goldstraw with a knife, demanding he hand over the watch.

As he was putting it in his bag, Mr ­Goldstraw ran outside, trapped him in the store and was helped to keep the door shut by a passerby.

Caine escaped after using a hammer to smash his way out.

Both DNA and witness statements linked him to the scene.

He was sentenced to four years in prison for robbery and six months for the attempted robbery, to be served concurrently.

Mr Goldstraw and his dad Paul, who founded the family business, attended every day of the week-long hearing, which included 25-year-old Jack being cross-examined by his attacker.

"I was overwhelmed by anger," he later told The Hunts Post. "For a guy who was inches away from me with a knife ­trying to say it wasn't him was borderline ­comical.

"I recognised him as soon as he opened his mouth. I didn't have any doubts."

Mr Goldstraw said the nature of the ­business meant he had thought about it being a target for thieves.

"We are working with luxury items and people are desperate, so we're always ­prepared.

"But it doesn't matter how much you ­prepare for these things you never know how you will react.

"My number one emotion was anger towards him.

"How anyone can have the nerve to come into a family-run business and rob from us really did anger me.

"Now he's in prison, it's closure as much as it can be."

Paul Goldstraw, who described the trial as extremely traumatic, said: "Four years for a young man of 23, I hope it has a positive effect on him.

"Hopefully, it will prevent him from doing it to anyone else."

Mr Goldstraw senior admitted he had contemplated closing the business after the attack but had been persuaded otherwise.

"One of the most humbling experiences was the number of people who came in to offer support and ask us not to close," he said. "It was truly incredible."