Greatest show on Earth

The countdown to Live8 was under way last night - with millions of music fans worldwide gearing up to watch the greatest rock show on Earth.

But there were remarkable preconcert performances from Tony Blair and Madonna ... both with egos very much to the fore.

Alongside Bob Geldof, the beaming Premier was in excruciatingly trendy mode as he appeared on a programme for the MTV music channel in which the two men were quizzed by young people about African poverty.

Meanwhile, Madonna seemed to have reverted to her direst diva ways - trying to book herself an astonishing six hours of rehearsal time on the Live8 stage in Hyde Park despite there being a logjam of other big-name artists wanting to practise their sets.

On the MTV show - which will be broadcast tonight - Mr Blair at one point leaned forward as he sat on a bright orange bench to show off the white Make Poverty History wristband he was wearing on his left wrist. And he somehow kept beaming when Geldof rested his head on his shoulder.

The PM's grin was still there as he took pre-recorded questions by video from the pop group Destiny's Child. But the smile fell from his face when hip-hop star Snoop called him 'Prime Minister - or is it President? - Tony Blair'.

However, he was given a boost by Live8 organiser Geldof, who appeared to let him off the hook over Africa and climate change.

The rock star said he knew the Prime Minister would try his best to reach agreement with seven of the world's most powerful leaders at the G8 summit in Gleneagles next week.

Geldof added: 'He is going to a fivestar hotel on a golf course and saying to seven guys, "I came with the largest ever mandate collected in the history of this planet to do this." They can refuse to accept that. If they refuse, he can walk out and say he tried.

'I think it is fair for him to say. "I tried, they refused." I would back him up, because I know the

process.' Whether the famously volatile ex-Boomtown Rats singer would have taken a similar concilatory line with Madonna is unclear.

With 25 top stars crammed bumper to bumper on the Hyde Park line-up, he had made it clear there would be no room for any diva-style antics.

But with names like Sir Paul McCartney, Dido and U2 all clamouring for any time at all to rehearse on the park's stage today, Madonna decided she was going to need a full six hours of rehearsal time to get her complicated act right. Organisers were flabbergasted, because she is due to perform just three 15 songs in a 15-minute set.

After several tetchy hours of negotiation, the star - said to be nervous because she has not appeared live for months - was eventually given an hour of rehearsal time.

The Hyde Park concert will be the centrepiece concert of ten Live8 gigs around the world aimed at getting action on Third World poverty.