by Kevin Smith and published in The Guardian, Friday 27 February 2009

According to your news report, there is concern at Metropolitan police headquarters that green activists could soon be "joining forces" with "middle-class campaigners" over issues such as Heathrow's third runway, leading to "angry demonstrations" that could "open the door to powerful coalitions" (Britain faces summer of rage - police, 23 February).

Superintendent David Hartshorn says: "Middle-class individuals who would never have considered joining demonstrations may now seek to vent their anger through protests this year."

Hartshorn is one of several senior officers who have, in the past months, attempted to frighten people into not protesting about climate change. Late last year an Observer article claimed that police were "concerned a 'lone maverick' eco-extremist may attempt a terrorist attack aimed at killing large numbers of Britons". The story was based on a "senior source" in the police's National Extremism Tactical Coordination Unit, but the unit later said the report "wasn't an accurate reflection of its views" and the Observer withdrew it.

Now, the police, it seems, are exploiting the recession-provoked threat of social unrest. This week's article refers to intelligence reports of "known activists" who, according to Hartshorn, "would be good at motivating people, but they haven't had the 'footsoldiers' to actually carry out [protests] ... Obviously the downturn in the economy, unemployment, repossessions, changes that". And he cites "elements" that will supposedly "hijack" an otherwise peaceful protest and "turn that into disorder".

Every year the existence of a supposed "hardcore minority" with the power to subvert the masses is raised as an excuse for heavy-handed policing against anyone engaging in protest. There's never been any evidence to support the existence of these powerful and sinister protest svengalis planning to brainwash the masses. At our Heathrow camp the drip-fed stories were that we would use bomb hoaxes. Nothing of the sort happened. At our Kingsnorth protest, we'd turned into knife-wielding thugs. Again, it was all in the imagination of senior police officers.

The Home Office told parliament that 70 officers had been injured while dealing with protesters at Kingsnorth. The real number was zero (officers had in fact suffered injuries at the hands of a wasp and a van door). The Home Office apologised for misleading parliament.

In reality the people involved in the climate camp at the G20 meeting in London on 1 April (the protest causing most concern, it seems, to Hartshorn) are committed, just as we were at Kingsnorth and Heathrow, to pushing for real action on climate change by practising civil disobedience. To claim that they would willingly be recruited by a machiavellian cadre of "known activists returning to the streets to foment unrest" is a smear that holds no weight.

The police are supposed to operate on evidence, not on febrile imaginations. Hartshorn's comments are yet more evidence, as former MI5 head Stella Rimington put it, that people in the UK are made to feel that they "live in fear and under a police state". The 1 April protest will be about carbon markets, taking climate change seriously and, it seems, democracy itself.

• Kevin Smith is a participant in the Camp for Climate Action  press@climatecamp.org.uk