Activists are hopeful a High Court ruling about police treatment of anti-war protesters will lead to change in the tactics used against them.
The ruling could have implications for detention of May Day protesters
Judges ruled police were wrong to detain protesters on their way to a demonstration at RAF Fairford in Gloucestershire last year.
But they said officers were within their rights to turn people away from such a gathering.
Gloucestershire Police said the ruling vindicated their officers' actions.
John Halford, the solicitor who acted for protesters, told BBC News Online the ruling would force changes in police strategy.
"The implications are quite important. It's now a fairly common police tactic to contain groups of people in circumstances where they think the demonstration might not go as they like.
"In May 2001, in Oxford Circus thousands were corralled for several hours."
Mr Halford said it was the first time an issue related to this had been considered and it would have implications for civil cases on that matter this year.
"The detention is not compatible with common law or the Human Rights Act.
"It gives the police very little scope to detain groups of people."
But Mark Littlewood, of Liberty, said it was not a conclusive victory for the protesters.
"They've won damages, the police have been obliged to pay costs.
"What the court has decided is that it was probably acceptable to stop them getting to RAF Fairford but it was wholly unacceptable for police to put them back on the coaches forcibly escort them all the way back to London and prevent them even stopping for toilet breaks.
"I very much hope Gloucestershire police don't appeal.
"This defeat for heavy-handed policing should allow police across the country take a step back and consider exactly how they are handling protests, particularly anti-war demos."
Protester Jane Laporte said those who had taken legal action over being held in Oxford Circus would benefit from this latest ruling.
"We are definitely overjoyed in respect of the arbitrary detention but we are disappointed we didn't get a ruling in our right to protest and lawful assembly.
"It will mean the police will have to think carefully about how they do things. It won't be a tactic the police would use in future."
A spokesman for the Association of Chief Police Officers (Acpo) said it was too early to say how future policing operations would be affected.
But Gloucestershire Police said there was no criticism of them in the judgement.
"In its judgement the court has made it clear that the operational commander on the ground was lawfully entitled to turn those coaches away. In fact, it was his duty to do so.
"While the court has decided that it was wrong for the police to escort those coaches back to London, they made it clear that there was no basis whatsoever for doubting the Operational Commander's intentions or motives in doing so. He was acting in entirely good faith."