Anarchists are of course no strangers to being infiltrated by the state. Their ranks have been penetrated by informers and agent provocateurs for more than a century.

They have been one of the most common targets of the infiltration operation by undercover police officers that has been running since 1968.

We have written about four of the undercover police officers in our book, Undercover. The most recent known undercover officer worked under the fake name of Mark Jacobs, and pretended to be a member of a small group of anarchists in Cardiff from 2005 to 2009.

Two police officers from the Special Demonstration Squad posed as activists in Class War in the late 1980s and early 1990s.

Another spy from the SDS is recorded as "successfully" infiltrating another anarchist group, the Direct Action Movement, between 1990 and 1993, according to an internal Special Branch document.

I am interested to hear of any more information about this infiltration if you wish to get in touch.

A little while ago, I was interviewed by an anarchist radio show. I thought I would post a link here to the interview as it gives an overview of the story of how the police have sent undercover officers into political groups over the last four decades.

Turn On, Tune in and Kick off is the motto of the Circled A show. This here gives you an idea of what the show is about.

The show is broadcast weekly (and can also be downloaded afterwards) on Resonance FM, which describes itself as "the world's first radio art station, established by London Musicians' Collective ...to provide a radical alternative to the universal formulae of mainstream broadcasting."

The interview with Yodet and Janey from the show lasts nearly an hour. I appreciate that it is quite long, so here's a guide to the order of the topics discussed to give you a flavour of it.

* how activists unmasked Mark Kennedy, the police spy who infiltrated environmentalists for seven years;

* Peter Francis, the only undercover officer who has blown the whistle on the infiltration operation;

* how police are alleged to have passed on information about campaigners to a secretive agency which blacklisted workers;

* the calls for a proper public inquiry into the undercover spies and the question of whether the police should be allowed to investigate themselves;

* the range of political groups infiltrated by the undercover spies since 1968;

* how the spies such as Kennedy and Bob Lambert duped women into having long-term relationships with them;

* The theft of dead children's identities by the spies to use as the basis of their fake personas;

* the police's use of informants in political groups;

* the deployment of corporate spies such as Rebecca Todd in political campaigns.

The song at the start of the interview is particularly worth catching. The second part of the interview is to be broadcast tomorrow.