Tube managers are drawing up contingency plans in case the extension is not finished in time to carry visitors to and from the Millennium Dome.

Junior Transport Minister Glenda Jackson used a Commons written answer to disclose that she has asked London Underground to produce emergency measures in case the project, dogged by delays, is not finished by New Year's Day 2000.

It was due to have been completed by March 1998.

News of the contingency plans comes after the Tube's new managing director, Derek Smith, conceded the Jubilee link might not be open in time for the opening of the Dome in Greenwich, south east London.

The Dome and its surroundings were designed with the Tube in mind as a chief means of access

The government has been hoping most of the visitors will travel to the Dome on the Jubilee Line.

The Dome itself and the surrounding nearby areas have been designed with public transport, particularly the Tube, in mind as the main means of access.

Ms Jackson told MPs it would be "irresponsible" not to have contingency arrangements in case there were transport problems.

"I therefore asked LU, through my Millennium Access Co-ordination Group, to lead the production of contingency plans for this and other eventualities."

She added: "LU have, in association with London's other transport operators, developed plans to cover a wide range of possible scenarios and identified an underlying command and control structure to direct the plans, should they need to be involved."

An overview of the plans had been submitted to the government and the finished plans should be in a "state of readiness" this autumn, she said.