A t-shirt brought detectives to Lesley Rogers' door. She was wearing it when she was stopped by traffic police in Glasgow. The discussion quickly turned to the G8.

She said: "That led us to have a discussion about what we were doing, what was the opposition to G8 and we spoke about police brutality in previous G8s."

Lesley is involved with Dissent, one of the more radical groups planning protests against the G8. It has made no secret of its desire to blockade roads near Gleneagles and in cities where delegates are staying. Lesley told the traffic officers that she has trained as a street medic - someone who could treat people who're injured or take ill during demonstrations. A few days later detectives were asking if she knew of anyone who was planning to attack the police.

She said: "I take part in many direct actions, whether it be with CND, Dissent or any other network. They're completely peaceful, and they're non-violent direct actions to raise awareness."

"I'm a mother of two I would not wish any harm on anybody and I certainly wouldn't want to be caught up in anything."

There was a knock on another door in Glasgow - this time detectives wanted to question Ashvin Devos. He had designed a website for G8 Alternatives, the group which is hoping to march past Gleneagles Hotel on the opening day of the summit. Again the police asked if he knew of plans for violence.

He said: "They weren't aggressive or anything like that. It was just the information they already knew about me which was kind of worrying. They had already accessed my e-mails and they were referring back to those during the interview which was three hours long."

The police believe a small number of protesters intent on causing trouble are heading to Scotland.

Chief Constable David Strang from the Association of Chief Police Officers said: "We have been collecting information whether in the newspapers or on websites and that helps us to plan for a safe and successful summit, so it doesn't surprise me that people have been asked about their involvement, no."

Some believe all protesters are being tarred with the same brush as the extremists.

John Scott from the Scottish Human Rights Centre said: "I think it's happening increasingly now. The right for peaceful protest is something that the authorities are resentful of. I think it's an irritation to them."

Frances Curran MSP from the Scottish Socialist Party said: "I think it's a creeping attack on our civil liberties. Bush is coming here and all of a sudden we're finding our democratic rights under threat."

Lesley Rogers said: "The concern so far has been about violent people coming to Gleneagles, well, there are violent people coming to Gleneagles. They come as the leaders of G8."

Security experts say MI5 and MI6 will be monitoring hardline protesters in Britain and abroad - the police will not comment on that - they say their number one priority is ensuring the G8 summit is safe and secure.

Lesley Rodgers and Ashvin DeVos were interviewed by officers from Strathclyde Police. Today the force said they were conducting on-going inquires and it would be inappropriate to comment any further.