The dispute centres on pensions and jobs

Kits designed to register if a person is over the legal limit to drive were handed out by police at Leicester Square station on Thursday night.

It coincided with the launch of Operation Cracker, a campaign targeting disorderly and alcohol-related behaviour in the run-up to Christmas.

Extra patrols will be at Tube stations and hot spots until Christmas Eve.

British Transport Police said dog units and community support officers will be involved in the operation.

Supt Andy Ball, said: "We don't want to be killjoys but it is important to remember that your right to party is only valid until it affects the safety and comfort of others."

BTP said incidents of assault and disorderly conduct can increase by as up to 9% over the Christmas period.

Jo Foule, 33, of Crystal Palace, said she had drunk half a bottle of wine during a business meeting and registered 33 micrograms, which is just below the legal driving limit.

"It's a great campaign particularly for women on their own who need to be conscious of their surroundings," she said.