We made the right decision to try for something bold and ambitious

Tony Blair

Mr Blair told the BBC's Breakfast with Frost programme: "It's not been the success we hoped," but added "neither has it been the disaster that it has been portrayed in some parts".

Speaking in Brighton, Mr Blair also refused to back down on petrol duty or his policy on pensions, despite calls for change from within Labour's ranks.

Mr Blair, speaking only days after cabinet minister Clare Short called the Dome "a flop", said if he had known in 1997 what he knows now about governments trying to run big leisure attractions he would have considered the project "too ambitious" .

Though stopping short of an apology, he said that as prime minister he bore the final responsibility for the difficulties of the Dome.

Shadow culture secretary Peter Ainsworth said the admission should be followed by an apology from Mr Blair.

"When are we going to see any minister shoulder the responsibility for this catastrophic fiasco?" he said.

Standing firm

During the wide-ranging interview Mr Blair also made clear his determination not to give in to pressure to restore the link between the rise in the state pension and earnings.

Defending current policy - which is likely to be the subject of heated debate at conference - Mr Blair said his government would continue to raise the state pension in line with inflation and target the poorest pensioners.

Turning to the anger from within the party and from pensioners sparked by this year's 75p increase in the state pension, Mr Blair acknowledged that it had sent the wrong message.

He said: "Although it was done absolutely according to the rules, pensioners perfectly naturally look at the 75p every week and don't take account of all the other things we are doing for pensioners."

But he said re-linking pensions to earnings would be unsustainable in the long run.

Difficult times

Addressing the dramatic change in the party's fortunes in the polls in recent weeks, Mr Blair predicted voters would back Labour after they examined the core issues of health, education and pensions.

He said Labour was seeing "difficult times" but was important to keep focused on the big issues.

When pressed on last week's allegations that Chancellor Gordon Brown had lied over the detail of the �1m donation to Labour from Formula One boss Bernie Ecclestone, Mr Blair dismissed the claims entirely.

The donation had not influenced government policy he said and added: "It's a lot of rehashed old stuff from three years ago, which we dealt with then."

The prime minister also acknowledged that there had been problems with the government's handling of the fuel blockades.

"We weren't quick enough off the mark," he said, but added that the 60-day deadline being imposed by protesters would not be an influence.

He added: "I believe that we won't face that situation again and the plans we are putting in place will avoid that."