DESCRIBING the circumstances of a robbery as "unusual," prosecutor Ron Ede told Truro Crown Court on Friday that on July 19 last 'Birmingham Ben' was in Westgate Street, Laun­ceston when he offered a knife for sale for £10.

John Archer borrowed the knife, held it at a youth's throat and demanded £10, which he then used to buy the weapon.

"Someone told Archer that that was not a very nice thing to do," whereupon he handed back the knife, retrieved the £10 note and gave it back to the loser," said Mr Ede.

Defending Archer, aged 28, of Robin Drive, Launceston, who had a previous conviction for robbery, Christopher Andrews stressed that it was not a pre-planned offence but was committed on impulse at a time when he was under the influence of drink.

Judge Graham Cottle told him that it was to his credit that he had pleaded guilty at the earliest opportunity, saving the police and Crown Prosecution Service a lot of work and a number of young witnesses from being involved.

"The circumstances are extremely unusual, but the victim would have been very frightened," he said.

"If I slavishly followed the guidelines you would be going to prison for several years, which would not be just. But there must be a sentence of 18 months."