A teenager has been jailed for 18 months for assaulting an off-duty police sergeant while trying to steal his bicycle on board a train.

Javid Ahmadzai, 19, of Havengore Avenue, Gravesend, pleaded guilty to assault with intent to commit robbery at Blackfriars Crown Court and was sentenced on Tuesday, May 20.

It follows a British Transport Police (BTP) investigation into the incident that occurred just after midnight on Sunday, August 4 at Abbey Wood railway station.

The court heard Sergeant Brian Washbourn, 42, who is based in Greenwich, was off-duty and travelling home from work at the time of the incident.

The Metropolitan Police Service officer intervened when Ahmadzai tried to steal his bike from the train carriage.

Detective Constable Mark Agrippa, of BTP’s robbery squad, said: “The victim boarded the train at Woolwich Arsenal station and placed his bike close to doors.

"When the train arrived at Abbey Wood, Ahmadzai and a group of men got off the adjacent carriage and while walking past the open doors attempted to grab the cycle.

“The victim intervened and was assaulted while trying to prevent Ahmadzai from stealing his bike. Thanks to the efforts of fellow passengers on the train, Ahmadzai left the scene empty handed.”

Ahmadzai was identified as the prime suspect after detectives circulated CCTV footage from the train to police officers in the surrounding area.

He was arrested in November and was charged on January 18.

DC Agrippa added: “This was a completely unacceptable assault. Members of the public have the right to travel on the rail network without the fear of violence and BTP will always fully investigate all such incidents.”

Speaking after the sentencing, Sergeant Washbourn said: “I'm pleased that my colleagues in BTP were rewarded for their hard work in securing this conviction.

"I was quite shaken by the incident and if it hadn’t been for the intervention of other passengers I fear I would have been seriously assaulted.”