London's Underground network will shut down this week for the second time in two months after talks again broke down in a dispute over all night services, trade unions said Monday.

There will be no Tube train services from Wednesday evening and all day on Thursday after three unions rejected a revised offer of terms and conditions for their staff.

The walk-out comes less than a month after a 24-hour strike in July saw the first total shutdown of the network since 2002, and will inevitably cause major disruption to millions of commuters and tourists in the capital.

Unions are locked in bitter negotiations with London Underground over plans by Mayor Boris Johnson to run trains all night on Fridays and Saturdays from September 12.

The drivers' union ASLEF urged the launch to be postponed pending further talks, after accusing management of being "completely inflexible" on terms and conditions.

"We genuinely regret the disruption this (strike) will cause," a statement issued by the union said.

"But the blame for this must rest with the pig-headed determination of the mayor to insist on a September launch instead of allowing more time for a negotiated settlement to be reached."

Critics of the strike action point to the relatively high salaries of Tube staff, but the unions insist the issue is not about pay but about work-life balance and safety.
London Underground chief operating officer Steve Griffiths said it had put forward an "extremely fair" offer which addressed these concerns.

"Despite this, the new offer has been rejected outright by the union leadership, again without consulting their members," he said, adding that he remained open to talks.

The strike will begin at 6:30 pm (1730 GMT) on Wednesday and services are not due to return to normal until Friday morning. Overground trains and buses will run as normal.