Police, council officials and organisers of the Edinburgh event will meet today for talks in an attempt to prepare for the rally which Scotland's First Minister warned must be "peaceful and respectful".

Jack McConnell sounded the warning in the Scottish Parliament as concern mounted over Sir Bob's call for a massive turnout in the capital. "I think it is absolutely critical any demonstration is peaceful and respectful - not least of those in Africa who are currently starving or dying," he said.

"They are the people it is meant to be all about.

"Whatever the numbers are, I want to see any organisers working closely with the authorities here."

David McLetchie, leader of the Scottish Tories, questioned whether the city could handle such a huge number of people.

He said: "We simply cannot have one million people turning up on the streets of Edinburgh without proper arrangements."

The scale of public enthusiasm for the Make Poverty History campaign and the sequel concerts to Live Aid has astonished even the organisers. More than 20,000 people a day are signing up to the MPH website, with millions expected to compete in a text message competition for the 72,000 tickets to the concert in London's Hyde Park.

The Prince's Trust charity, which had planned its annual Party in the Park concert for the same day, has decided to cancel the event and will receive a £1.6m donation from the money raised through the Live8 text competition.

Police in Edinburgh had expected 100,000 campaigners to descend on the city for the two-day summit of the world's most powerful leaders. The Chancellor had allocated £20m to the security operation.

With up to 10 times more people expected to flood into the city between 2 July and 8 July, the cost of the police operation is spiralling and according to some reports could reach £100m.

Make Poverty History organisers had planned a rally, march and concert in the city for 2 July, the day of the Live8 concerts.

However, Sir Bob seemed to take even his anointed organiser in Scotland, Midge Ure, by surprise yesterday when he called for a million people to make the "long walk to justice" and converge on Edinburgh by any means necessary on 6 July.

A spokesman for Live8 admitted there were no firm details of the Edinburgh event, and city councillors said they had not been forewarned by Sir Bob.

Downing Street insisted Tony Blair had been totally unaware Sir Bob would invite thousands of people to protest at the G8 summit.

A source said: "He had no idea about this. Who Mr Geldof invites to his parties is up to Mr Geldof, and the idea the Pope should make it his first gig is also entirely something for Mr Geldof."

The Live8 event in the Scottish capital will coincide with several planned direct action protests by more extreme anti-globalisation campaigners and could end in chaos, Assistant Chief Constable Ian Dickinson said.

Mr Dickinson said: "We may need to find additional police officers if large crowds are to be here for a longer period, and that may be difficult.

"There has been talk of up to a million people coming to Edinburgh, and frankly it is difficult to conceive how they could all get to this area in the first place and where they could assemble safely. No one wants tragedy to distract world attention from the aims of the campaigners."

But Mr Dickinson also moved to placate campaigners in the run-up to the Gleneagles summit by stressing that, unlike at other G8 meetings, protests would not be met with water cannons, CS gas or rubber bullets.

The annual meeting has previously been marred by violence in other host cities, such as Genoa, when an Italian protester was killed during the 2001 summit.

Organisers of Live8 are planning a peaceful rally in Edinburgh, 40 miles from the Gleneagles Hotel, but other protests timed for the same day could see more violent action.

One extreme group, called the Peoples' Golfing Association, has vowed to disrupt the first day photocall of the G8 leaders by invading the hotel grounds - the same day as the Live8 event.

The PGA, which describes itself as made up of "anarchist golfers", says on its website that the remote location and sprawling grounds of Gleneagles make it "particularly vulnerable" to direct action protests.

Another group, Dissent, has called for supporters to blockade roads around the luxury resort on 6 July, while other protesters plan to shut down the nearby Faslane submarine base.