Crime on London's buses is being cut after police officers began on-board patrols.

Officers have made 250 arrests and have helped prevent illegal parking in bus lanes since the initiative began in June.

The police currently ride on four of the city's most dangerous bus routes and a further 22 services are expected to be covered by March.

London mayor Ken Livingstone said: "This is another vital weapon in our armoury to tackle crime and congestion in London and I'm delighted by the results from the first two months.

"The unit is responding quickly to crimes as they happen and shows that by tackling apparently petty criminals you frequently uncover much more serious offenders."