A predatory sex offender who stalked and assaulted a teenager as she travelled to work has been jailed. 

Khurram Shahzad, of York Road in Ilford, was sentenced to 21 months behind bars after admitting two counts of sexual assault and one count of harassment at Blackfriars Crown Court on August 13. 

The 30-year-old was also placed on the sex offenders register for 10 years after the court heard how he preyed on a 17-year-old girl on her journey from Liverpool Street to Oxford Circus on the Central line. 

He first assaulted the teenager from Brentwood almost a year ago on August 30 after boarding the same carriage on a crowded tube journey into central London. 

Shahzad approached her from behind and started assaulting while other passenger stood close by, oblivious to what was happening.   

Detective sergeant Anna Fisk said: "The victim was so scared she was unable to react, she tried to move away from Shahzad but he followed her around the crowded carriage. 

"She got off the train at Oxford Circus and never reported the incident.

"Three days later, she was travelling on a westbound Central Line train at a similar time when she was again assaulted by Shahzad in a busy carriage. 

"The attack last several minutes and again, the victim was unable to escape due to other passengers stood close by."

For the next three days, the 17-year-old saw Shahzad again but she spotted him before boarding the train and was able to travel in a separate carriage. 

He was eventually caught on September 11 after the victim identified Shahzad to plain-clothed BTP detectives who had accompanied her on route to work. 

According the BTP's latest figures, reports of sexual offences on the Tube network have risen by 31 per cent since March last year, compared to the same period in 2012/13. 

Overall, sexual offences have risen by 21 per cent on Britain’s rail network.

To report any incidents of sexual assault, please text 61016 or call 0800 40 50 40. In an emergency always call 999.