A violent knife thug who posted pictures on Facebook from his prison cell should serve more time behind bars, says a furious MP.

Canterbury and Whitstable member Julian Brazier has written to the Justice Secretary today calling for tough action to be taken against Sonny Barker.

The cocky 20-year-old uploaded pictures to the social networking site using a phone smuggled in to HMP Rochester, where he is serving 12 years for aggravated burglary and possessing a knife.

The pumped-up crook was jailed last year after threatening a mum and her daughter with a knife after bursting into their Canterbury home.

His online boasts have sparked Mr Brazier to urge Justice Secretary Chris Grayling to increase the powers of prison governors to deal with such matters.

He said: “It seems to me that two things are needed here; first the toughest possible action against this thug who has cocked a snook at the criminal justice system, but secondly, an increase in the powers of governors to take tough action in this case.

“As you know, prisoners typically enjoy a 50% reduction in tariffs on sentences handed down by the courts.

“A generation ago, governors and boards of visitors had much greater powers to make offenders serve substantial portions of that period planned for remission, when prisoners committed offences inside prison.

“These powers used to be available without costly and burdensome references back to the courts.

“I have been told that the maximum addition to time served that Barker is likely to face for this offence may be only 42 days.

“Considered in the context of his history of violence, the length of his sentence and his defiance of the system, that seems grossly inadequate.

“Could I urge you to review and increase the powers available within the prison system to deal with disciplinary offences, so that future cases like this can be dealt with quickly and in a manner which deters further wrongdoing?”