Officers with specialist public order training will patrol troublespots

The Metropolitan Police sent extra officers into six London boroughs where large numbers of bars and clubs have seen big increases in violent crime.

The launch of Operation Optic comes as latest figures reveal a 140% increase in assaults on police officers.

The crackdown was launched on Thursday night to coincide with England's dramatic match against Portugal.

X-ray machine

Police teams with specialist public order training will patrol known troublespots with the help of hundreds more officers from local boroughs.

A new x-ray machine will be used to find out if people are carrying knifes or guns.

And on-the-spot fines will be handed out to drunk or violent offenders who could then be held in vehicles fitted with prison cells.

BBC correspondent Neil Bennett said the operation had been launched because Met Police chief Sir John Stevens, like many police bosses, was fed up with city centres becoming "war zones" at night because of binge drinking.

Pubs and clubs which continue to sell drinks to underage or clearly drunk people will be closed down.

The crackdown is set to continue every weekend in the boroughs.

'New British disease'

The operation follows in the footsteps of a nationwide blitz on drunken behaviour during Euro 2004 launched by Home Secretary David Blunkett.

Officers have worked closely with pubs and clubs during Euro 2004

Police forces across the country have been targeting alcohol-fuelled disorder in urban areas.

Mr Blunkett has previously said the drinks industry must play its part in a controlling on Britain's binge drinking culture.

The prime minister has also warned the drinks industry it could face a levy to help pay for cost of combating street trouble.

Last month, Tony Blair described alcohol abuse as fast becoming the "new British disease".