A pervert who exposed himself to women and masturbated on Tube trains has been jailed for 18 months.

Jacek Drzal, 32, of High Road, Willesden Green, carried out a seven-month spree of sitting opposite women on Jubilee and Metropolitan line trains before exposing and touching himself between December 2011 and July 2012.

But after officers from the British Transport Police spotted him boarding a train at Stanmore Station on the evening of July 26, hours after he targeted a 27-year-old woman, he was arrested.

Checks on Drzal’s Oyster card showed he would travel underground for hours at a time, and CCTV footage placed him at the scene of eight similar crimes reported to police by other victims.

Detective Constable Martin Chapman described how Drzal was arrested after he exposed himself to a woman on a northbound Jubilee line train after boarding at Kilburn at approximately 5.40pm on July 26.

He said: “He sat opposite his victim, a 27-year-old woman, who had fallen asleep. When she awoke, she saw him with his trousers pulled down, touching himself in front of her.

“The victim left the train at Stanmore and reported the incident immediately.

“Though he made no move towards his victims, or threatened them in any way, Drzal’s offensive and brazen behaviour quite understandably caused them considerable distress.

“Thanks to excellent CCTV at stations, as well as strong support from witnesses, we were able to seize vital evidence to help secure his conviction.”

At Blackfriars Crown Court on Tuesday, Drzal was sentenced to 18 months in prison and made to sign the sex offender’s register after pleading guilty to eight counts of outraging public decency.