Leeds Crown Court heard Sean David McDermott had made an unsuccessful attempt to rob a bus driver the previous evening December 13.
Jonathan Sharp prosecuting said when he got on the bus in South Elmsall around 8.15pm he pushed a knife through the security shield at the driver saying “I want your money”. He was offered a few coins but said: “You’ve got more money than that, hand it over or I’ll stab you.”
The driver pressed the panic button and McDermott fled.
It was around 1.45pm the next day he walked into the jewellers and asked if he could look at engagement rings.
The manager suggested he looked at them through the window but McDermott said he wanted to pay about £200 but needed to handle them.
A cabinet was unlocked and three rings were removed from the display. McDermott tried to steal the rings but was challenged by a member of staff. He managed to steal one of the rings and later tried to sell it at another shop.
Daniel Smith, mitigating, said McDermott lived for a time in Spain and “got involved with the wrong people and started using drugs.”
McDermott, 32 of Oulton Road, Wakefield, admitted robbery and attempted robbery. Judge Tom Bayliss QC told him there was no pleasure in jailing a man who had previously served his country well but was now a drug addict.