HUNDREDS of Metropolitan Police officers are heading north to bolster security at what is expected to be one of the biggest demonstrations ever held in Scotland.

Police believe as many as 200,000 people will take part in a march in Edinburgh in the run-up to the G8 summit at Gleneagles Hotel in July, and are concerned that violent protesters may seek to infiltrate the event.

A massive security operation is already being planned for the conference of leaders of the world's richest nations at the golf and hotel complex in rural Perthshire from July 6 to 8.

Authorities are trying to discourage protesters from converging on the area by giving the go-ahead to a main demonstration in Edinburgh instead.

It is believed Edinburgh University's Pollock halls of residence, which have more than 500 rooms, have been booked as accommodation for the huge influx of officers from the Met and other forces who will lend their weight to the security effort for the summit and associated demonstrations.

Security for Gleneagles itself will be under the operational control of Tayside Police.

Local MPs and MSPs with constituencies in Edinburgh and the Lothians were briefed this week by Lothian and Borders chief constable, Paddy Tomkins, and Ian Dickinson, assistant chief constable, who showed them footage of the violent riots which marred the G8 summit in Genoa in 2001 as an illustration of what can go wrong.

The umbrella organisation, Make Poverty History, which comprises most of the UK's mainstream charities and church groups, said it intended to make the demonstration on Saturday, July 2, family friendly and hoped this would help keep the protest peaceful.

Bruce Whitehead, of Make Poverty History, said the organisation had taken measures to try to make the event a success, and had co-operated fully with the police, who have kept the route of the march well away from the new Scottish Parliament building.

The demonstration is due to take place a week before the arrival of world leaders, including Tony Blair and George W Bush.

Mr Whitehead said that the organisers were aiming to create an atmosphere similar to the Fringe Sunday event.

"We are very clear that we are having a peaceful protest and we are determined that this should not be upset by a small minority."

However, although the UK arm of the movement is supported by charities such as Oxfam and Christian Aid, the worry for the police is that anarchists, anti-capitalist pro-testers and others prepared to use violence will take advantage of the scale of the demonstration to spark off riots.

The organisers of the protest are aiming for more than 100,000 participants, but police told MPs and MSPs this week that the size of the event could reach 200,000 because of the focus on world poverty brought about by the tsunami disaster in the Indian Ocean and the fact that both the prime minister and Gordon Brown have made tackling the plight of Africa one of the key themes of Britain's presidency of the G8.

The crowd in Edinburgh could also be increased by the participation of major-league celebrities such as Bono of the band U2. Yesterday, the Irish rock star shared a platform with Mr Blair, Bill Clinton, the former US president, and Bill Gates, the Microsoft founder, at the world economic forum's annual gathering when they urged the world to take a "quantum leap" in fighting poverty in Africa.

Lothian and Borders Police said: "Protest is to be encouraged, providing it is peaceful."