Scotland faces massive disruption, with motorways blocked and city centres coming to a standstill, when it plays host to the G8 summit of world leaders this summer. That is the warning from anti-globalisation protestors, opposed to the gathering which takes place at Gleneagles in July. Over the weekend, activists met in the small German town of Tübingen to discuss tactics.

Tübingen is a small university town in southern Germany that is well used to discussion and debate, but the items on this weekends agenda were unlike anything the town had seen before.

For the past two days, around a hundred people opposed to the G8 summit, which takes place in July at Gleneagle, have been meeting in this building, exchanging ideas and working out how best to disrupt a gathering of the world's most powerful leaders.

The meeting in Tübingen was organised by Dissent!, an umbrella organisation for activist groups. They declined to be interviewed, but on the group's website, their aims are spelt out. "The G8...will not pass by uncontested" they declare, adding that they believe in "A confrontational attitude, since we do not think that lobbying can have a major impact in such biased and undemocratic organisations..."

One activist who did agree to speak was Stefan George, a university lecturer from Berlin, who's sceptical of the G8, a group he regards as deeply undemocratic. He said: "It's a closed setting of people, of government people, and I think it has to be more transparent, because I don't know if they can express what the public says."

Asked how important is was to be organised before coming to Scotland, he replied: "I think it's organised because the other side is organised too, so they have to see how they can make it to Scotland, how they're building that up."

Previous G8 summits have witnessed riots and death - one man was killed in the Italian city of Genoa in 2001, and dozens injured. Those who study how such events come about believe similar scenes here in Scotland are almost inevitable.

Rob Brown, a media lecturer at Napier University, said: "It has to be acknowledged that the mainstream media likes nothing better than conflict and chaos, that makes good television pictures, and the activists know that, they know how to get on to TV screens, and if they do that in Scotland in the way that they've become accustomed to doing, then we could see some serious disturbances here in Scotland."

But others are determined those intent on violence do not hijack events, such as an anti-poverty march through Edinburgh that's expected to attract 200,000 people.

Gill Hubbard from G8 Alternatives said: "The majority of people are there to peacefully protest, and it's the same people that were protesting against the war, and have been giving in their millions to the tsunami appeal, ordinary people are really concerned about these issues, and that's why they'll be joining the peaceful protests."

But whatever their tactics, protestors are determined their voices will be heard.