However, uncertainty still dogs the future of the project. Mr Blair said it was dependent on the scheme meeting five criteria of viability. Millennium Central, the exhibition organiser, was prevented from issuing details of the project because of ministers' concerns about the contents of the Lord Rogers-designed dome.
The pounds 838m project, which had been in danger of being abandoned following a comprehensive review, will be relaunched next week and new executives brought in to run it.
New designers are also expected to be brought in. The fact that so much still remains to be decided for the project, which must be completed by September 1999, compounds the personal risk taken by Mr Blair.
Under the new criteria, the project must have a lasting legacy; its content must be improved; based on the concept of "giving Britain a window to the future"; the nation must be included; there must be new management; and there must be no public expenditure apart from pounds 20m spent on land reclamation.
The National Lottery Fund has already allocated pounds 200m plus a further pounds 250m which would be available if needed but is almost certain to be used. Ticket sales are expected to raise about pounds 200m, which on the calculation of 10-12 million visitors assumes that entry will cost around pounds 20.
While Chris Smith, Secretary of State for National Heritage, will remain in overall charge, Peter Mandelson, Mr Blair's ministerial bagman, will be in charge of pushing the plans through.
David Quarmby, chairman of the British Tourist Authority, welcomed the move, saying the Millennium Exhibition "will be the jewel in the crown of Millennium year in Britain and could account for bringing an additional pounds 300-pounds 500m of overseas visitor revenue to Britain in the year 2000."
London First, which represents business in the capital, said it welcomed the decision but warned: "The private sector must now be fully involved in the way that it has not been up to now with both the funding and management of the project."
However, Opposition sources hinted that Labour had been playing a double game when it cast doubt on the future of the exhibition during the election.Reuse content