A teenager who threatened to kill a post office worker in a terrifying armed robbery was identified by his 'L'-plate moped and distinctive jacket.

An eagle-eyed police officer recognised the description of the getaway vehicle as one he had stopped just two days before the raid at the store in Broadstairs.

Having also viewed CCTV and compared the crash helmet-wearing robber's distinctive Mercier-branded clothing to photos on social media, the constable was able to name Harry Marshall as the perpetrator.

As a result, the 19-year-old was arrested just four hours later, and found stuffed down a sofa where he had been sitting was £200, with a new £10 note in his wallet.

Marshall, from Deal, later pleaded guilty to robbery, possessing a bladed article and possessing an offensive weapon.

Canterbury Crown Court heard that the Dumpton Post Office in Ramsgate Road was targeted by the teen and a male accomplice at around 6.40am on August 3.

Marshall, dressed in black, wearing gloves and with his dark visor pulled down, was brandishing a large knife with a 6 to 7in blade as the second man stood close to the door.

Prosecutor Simon Smith said the youth then began to threaten the lone staff member.

"Marshall was pointing and waving the knife, saying words to the effect of 'I want everything. Give me everything you have or I'll kill you. If you don't give me everything I'm going to f***ing kill you'," he told the court.

"He then pulled down the plastic covering at the till area, giving him access to jump over the counter.

"The member of staff was clearly frightened and pressed a button allowing the till to be opened. Marshall reached in and removed all the bank notes to a total of £1,800.

"Both men then ran out of the store and CCTV and a member of the public saw a black moped being driven away."

The court heard that, during the commotion, Marshall dropped an extendable baton on the post office floor.

Detailing how he was then identified and arrested, the prosecutor continued: "The moped didn't have a registration number but had an 'L' plate taped to the front of it.

"A local police constable recalled a previous incident on August 1 whereby he stopped Marshall on a moped matching that description.

"On viewing the CCTV and the distinctive logo on the clothing, a comparison was made with various social media photos which led police to believe Marshall was the man they were after."

Marshall, of Fairfield Road, Hay Hill in Ham, was then found just a few miles away.

Although some cash was found down the side of the sofa, the remaining money stolen was never recovered.

The post office worker was said to have been left shaken by his ordeal, while the owner revealed that he and his staff were "frightened and nervous", and feared being targeted in the future having previously been burgled twice in 2019.

The court heard that other than a conviction in January this year for possessing cannabis for which he had been given a 12-month conditional discharge, Marshall was of good character.

The reason for his involvement in the robbery, however, was "overwhelming" pressure from others to pay off a drug debt, said Kevin Walsh, defending.

He told the court that having been beaten up, the now 20-year-old, who suffers from autism, "took an opportunity" to repay what he owed and landed himself behind bars.

Expressing Marshall's deep regret and remorse, as well as his progress while on remand in custody, Mr Walsh added: "In some ways he has been lucky because the path he was on was further drugs.

"Because of his autism, the constant noise and aggravation means prison is much more difficult for him with the various triggers and stimulants.

"Marshall’s despicable actions that day have had a lasting impact on his victim…”

"He cannot escape them and so his punishment is exacerbated. It is his sincere wish never to come before the court again. There is real remorse."

Locking Marshall up for two-and-a-half years, Judge Sarah Counsell told him that although the robbery was "relatively unsophisticated", it had "terrified" post office staff carrying out a public service.

She accepted however that but for his involvement with drugs and being groomed by "more sophisticated criminals", he would not have been standing in the court dock.

"It would be inexplicable otherwise for a man of 20 with one conviction for possessing cannabis being sentenced for armed robbery of a post office," added the judge.

Speaking after the sentencing hearing, Detective Sergeant Vanessa Law said: "Marshall put his victim through a frightening experience, making him believe he would be harmed if he refused to hand over the money from his business.

"Marshall’s despicable actions that day have had a lasting impact on his victim and it is right that a custodial sentence has been imposed. We will always strive to bring offenders such as Marshall to justice."