A dangerous criminal who has targeted people and shops in Norwich since the 1990s has been jailed for an extended 10-year sentence after robbing an 18-year-old cashier with a water pistol.

Ryan Smith, 42, carried out his 13th city robbery on July 9 and was jailed at Norwich Crown Court on Wednesday.

Despite his plea that he had been coerced into the robbery through threats of violence, Smith was deemed a 'high risk to the public' after robbing the teenage member of staff at the Catton Grove Co-Op.

Chris Youell, prosecuting, said Smith entered the shop around 8.45pm, and as the cashier turned to get him a pack of Old Holborn, slipped a note and carrier bag onto the counter while flashing the black handle of what appeared to be a pistol.

The note read: 'Put the money from the till in the bag, keep quiet and nobody gets hurt'.

£500 was stolen from two tills, in a robbery which had the hallmarks of Smith's previous robberies, Mr Youell said. 'He has been released on licence and done it yet again,' he said.

'He started committing robberies in 1998. He began with knife-point robberies of people on buses or at cash points. He moved on to robbing shopkeepers.

'There were two robberies of lone women in shops in 2013 and with no suspects at the time, a retired detective constable recognised the description and as a result of what he told colleagues, Mr Smith was arrested.'

Andrew Oliver, mitigating for Smith, said he had 'tried to settle down' after release from prison in summer 2017 but had been tracked down by 'a gang who had supplied him with drugs in custody'.

'A large amount of pressure was put on him to pay the debt which had accumulated to £1,000,' said Mr Oliver.

'He had suffered at least two serious beatings and had tried to take his own life in an effort to relieve his immediate family from the pressure he felt he was being put under.

'He was told his mother was going to have a gun put to her head and his partner would be seriously sexually assaulted. These were matters he reported to the police before this offence.' Mr Oliver added Smith could have 'a fighting chance' if his next release was more effective.

Judge Anthony Bate jailed Smith, of Jewson Road, for six years with an extended jail term of four years for robbery, and a concurrent six-year sentence for the imitation firearm.