Young troublemakers should lose their free travel cards, Conservative London mayoral candidate Boris Johnson says.

Mr Johnson said the plan to remove free bus travel for any young people abusing it aimed to end rowdiness and violence faced by commuters.

He said anyone who lost their travel pass would have to do community service to get it back.

The community service could include graffiti removal.

Mr Johnson said he would also push to have Police Community Support Officers take more of the paperwork facing sworn officers, releasing them to get back out on the beat.

A spokesperson for Mayor Ken Livingstone's campaign said travel cards were already being confiscated.

She said anyone cautioned by police or convicted of a criminal offence lost their pass permanently, a stronger deterrent than that being proposed by Mr Johnson.