Like the feature article on this case:

 http://www.indymedia.org.uk/en/regions/sheffield/2009/04/427421.html

The Guardian mentions the M1 case:

"Sometimes these cases – such as the conspiracy to commit public nuisance charge brought against members of the "No M1 Widening" campaign in 2007 – are just thrown out by the judges. But sometimes, as in the conspiracy cases against animal rights activists and anti-arms manufacturing campaigns, they are treated extremely seriously. The impact on the lives of the accused is enormous, because under the terms of a conspiracy charge, you can be forbidden to talk to anyone involved, which can involve housemates, family, friends. Your possessions can be seized (Julie White of the M1 campaign had her door broken down by police, her computer seized and held for a year, and even items taken off her washing line) and held on remand for the duration of the trial."

...

"if the court allows the case and convictions follow, it has catastrophic implications. Any activist involved with planning any kind of illegal direct action could be charged with conspiracy to commit aggravated trespass.

As White says: "You could pick up anyone you wanted. We're getting into thought crimes now." Is that what the police are after?"