Standing at the despatch box in the House of Commons on Monday, he denied newspaper reports that one of the project's major private sponsors - telecommunications giant BT - was about to pull out.

Mr Mandelson, who has responsibility for the Dome, which is under construction in south London, said BT was a "company of the future - confident and vibrant - like the new Britain".

It was staying within the vanguard of the scheme, he said.

Peter Mandelson

Meanwhile, organisers of the £750 million project, revealed the line-up of celebrities and experts called on to advise on what should go inside the controversial exhibition space.

Among them are a film producer, a newspaper columnist and a former children's TV presenter.

The Millennium Dome, to be sited in the London suburb of Greenwich and opened for the year 2000, has long been dogged by controversy.

The latest row surrounds reports in some weekend newspapers that BT was on the verge of withdrawing its £12 million sponsorship.

Mr Mandelson, the government's Minister Without Portfolio, acted to reassure MPs that BT was still on board.

Construction on the Dome site in Greenwich

In the Commons he said: "Prospects for private sector investment are very good indeed despite reports today concerning BT - which I spoke about this morning to Sir Peter Bonfield, the chief executive of BT, who is absolutely categorical and said: `No we are certainly not going to pull out'."

Peter Mandelson: "BT are a company of the future" (0'21")

BT was not "a company of the old school, of the old Britain, unconfident and unambitious," he said.

He also rejected the notion that public spending on the Dome would top £700 million.

He said "as little as £399 million" was coming from National Lottery funds - not public spending - and the rest would be from private sector sponsors, commercial income and ticket sales.

The main pillars for the Dome are now in place

To taunts and laughter from both Labour and Tory MPs, he denied claims that the Dome had been a "presentational disaster". And he refused to be drawn on what visitors might find inside the huge structure come the turn of the century.

Meanwhile, the names of those who can expect a sneak preview of what is in store have been announced.

The 11-strong Creative Review Team will advise organisers on the "coherence, quality, entertainment and educational potential" of exhibition plans.

The group, whose members are unpaid, is expected to meet on a monthly basis until the Dome opens in 2000.