The intention is to make Londoners feel safer on public transport

Uniformed and undercover officers will patrol public transport in Brent, Westminster, Hackney, Lewisham, Camden and Hammersmith and Fulham.

They want to cut down on assaults and are looking for those carrying weapons or drugs.

More than 100 police officers will be joined by revenue protection officers from Transport for London (TfL).

Assistant Chief Constable Paul Nicholas said: "As Christmas approaches more and more people use the public transport system in London.

"They need to know they can do so in safety."

The Metropolitan Police's transport crime unit made 3,400 arrests across London between 10 June 2002 and 31 October 2003.

The campaign starts on the same day taxi touting becomes a recordable offence.

Minicab drivers caught touting for business will have their fingerprints and DNA details entered on the national criminal database.

It follows safety campaigns in London to reduce the number of sex attacks involving illegal minicabs.