A BEXLEYHEATH sex offender who masturbated in front of a teenager on a bus has been sentenced to six weeks in prison.

Michal Kowilski, 29, also admitted putting his hand up a 13-year-old girl’s skirt on a bus through Bromley in a separate incident two-and-a-half years later.

The chef initially escaped justice for exposing himself to a 16-year-old girl on April 7, 2011, because police arrested another man who was using an Oyster card with the same name.

But he was detained and charged after a teenager on her way to school on the 320 bus on October 23 last year accused him of grabbing her bottom.

In the first incident the victim was travelling at the back of the 51 bus at around 1pm as it passed through Sidcup High Street, Bromley Magistrates’ Court heard on Friday.

Prosecutor Leena Verma told the court: “She noticed the defendant moving his arms about.

“When she looked again, she saw he was masturbating.

“She said she was shocked and went to the bus driver to report the incident to him.”

When confronted Kowilski, of Woolwich Road, Bexleyheath, denied the offence and claimed the victim was lying before getting off the bus and walking back towards Sidcup.

On October 23 he was on the 320 as it drove through Bromley High Street at around 7am.

His victim came downstairs with her younger brother when she noticed Kowilski staring at her.

Miss Verma said: “She smiled at the defendant and as she passed him she distinctly felt the defendant grab her bottom and squeeze it.

“She shouted ‘what do you think you are doing, you paedophile’ but the defendant did not respond.

“When interviewed by police, he said didn’t touch the schoolgirl and his intention was to take a picture up her skirt and he had a mobile phone in his hand.

“He said he was hungover and still possibly drunk having consumed vodka the previous evening.”

Unemployed Kowilski also claimed he was hungover during the first incident, had been taking the horse tranquiliser ketamine and “had not been with his girlfriend for a while”.

Mitigating, solicitor Christopher Carter said: “The offences are both abhorrent.

“My client accepts responsibility for his behaviour and is very sorry for his actions.

“He is ashamed. He recognises he has a problem and wants to address the problem.”

District Judge Robert Hunter sentenced Kowilski, who has no previous convictions, to six weeks in prison and ordered him to sign the sex offenders’ register for seven years.

On December 20 last year Kowilski pleaded guilty to an act outraging public decency and sexual assault on a female.