Chris Smith: Temporary caretaker

Mr Smith cannot take up the job on a permanent basis because he is also chairman of the Millennium Commission, which distributes National Lottery money to the multi-million-pound project.

The government will announce a long-term appointment in the near future.

As he is no longer a minister, Mr Mandelson is not qualified to hold the government's single share in the New Millennium Experience Company, which is running the £758m project.

Mr Mandelson was a high-profile supporter of the Dome, but his position came under attack by political opponents, who said it conflicted with his duties as Trade and Industry Secretary.

But the NMEC's chief executive, Jenny Page, praised Mr Mandelson's support for the exhibition, which is due to open on 31 December 1999 in Greenwich, south London with a dazzling party.

She also said he was not involved in negotiating or procuring sponsorship contracts for the Dome.

"All contracts were handled by the NMEC in-house sponsorship team," she said.

She insisted that despite Mr Mandelson's departure, it was still very much "business as usual" for the Dome.

Mandelson defended British Airways' sponsorship

Mr Mandelson held the single share since 26 June 1997.

He saw the ambitious project as a chance to emulate his grandfather, former Labour Cabinet minister Herbert Morrison, who masterminded the 1951 Festival of Britain celebrations.

After he took up the post, he made assurances over British Airway's sponsorship of the Dome. At the time, the Department of Trade and Industry was due to rule on the possible threat to competitiveness of British Airway's proposed link-up with American Airlines.

Tories attack Granada deal

Last week, Conservatives criticised an announcement that Granada had won a lucrative catering contract at the Dome.

They pointed out that the award had gone to a company whose chairman, Gerry Robinson, had prominently campaigned for Labour in the 1997 general election.

The decision had shown "the conflict" between Mr Mandelson's twin roles as Trade and Industry Secretary and Dome supremo, said Conservative culture media and sport spokesman Richard Spring.

£30m publicity campaign

The NMEC is close to hitting the £150m sponsorship target it needs for the Dome.

The massive structure - big enough to contain two Wembley Stadiums and 13 Royal Albert Halls - is expected to attract at least 12 million visitors throughout the whole of 2000.