The Ratcliffe article contains:

Police launched a covert snooping operation on the plot to break into Ratcliffe-on-Soar power station before many of the activists had even thought of taking part...

A police report leaked to the Guardian shows how Mark Kennedy, the Metropolitan police officer sent to spy on the environmental movement, immediately tipped off his handlers about the idea. "This initial intelligence was nonspecific," the report records.

By the end of the month, the police had debriefed their spy twice on the fuzzy plans. By 5 November, they had applied for legal clearance to deploy Kennedy to gather intelligence on the proposals.

Activists say that the decision to target Ratcliffe was made in January 2009, when organisers were taken to the power station.

 http://www.guardian.co.uk/environment/2011/jun/07/mark-kennedy-ratcliffe-on-soar

The tapes article contains:

Kennedy's tapes were secret evidence that could have exonerated six activists, known as the "deniers" because they claimed not to have agreed to join the protest. The activists were among those prosecuted and due to stand trial in January 2011.

"During that briefing Spencer was very clear that this was a volunteer-only operation and it was down to the individual to decide what role they wanted to play," Kennedy said subsequently. "There was no pressure on anybody to take part in anything they didn't want to do.

"The truth of the matter is that the tapes clearly show that the six defendants who were due to go on trial had not joined any conspiracy. The tapes I made meant that the police couldn't prove their case. I have no idea why the police withheld these tapes."

But evidence gathered by the Guardian now suggests it was the Crown Prosecution Service rather than the police that withheld the tapes.

The new evidence is contained in confidential documents including recent correspondence between Chris Eyre, Nottinghamshire's deputy chief constable, and Judith Walker, the chief crown prosecutor in the east Midlands.

The documents suggest police handed over the transcripts of Kennedy's tapes as far back as May 2009. Senior officials also held a number of high-level meetings with police about the undercover officer's potential impact on the trial. The documents also reveal that the CPS may also have misled Nottingham crown court into thinking prosecutors only became aware of the Kennedy tapes in January this year....

Kennedy's draft witness statement was apparently not handed to prosecutors, but instead placed in a Nottinghamshire police safe. But, according to the documents, the material did include DVDs with intelligence listed as "a list of telephone calls" and the crucial "transcript of the recording" made on his watch, referred to by the code "130409/MARK".

Last October a message was posted on the Indymedia website by activists who had concluded the man known as Mark Stone was in fact a police infiltrator.

 http://www.guardian.co.uk/uk/2011/jun/07/mark-kennedy-police-spy-secret-tapes

The CPS article contains:

...the supposedly new evidence – the Kennedy tapes – had in fact been in the possession of the CPS for more than a year.

Prosecutors had taken part in a number of high-level meetings with police about Kennedy's potentially explosive surveillance tapes, but withheld them from defence lawyers.

Confidential correspondence between senior police and prosecutors suggests officers told the CPS about Kennedy's deployment from the outset. The police say they handed over a transcript of his secret recording to Ian Cunningham, a senior CPS prosecutor, within weeks of the raid...

Kennedy speculated earlier this year that the tapes may have been withheld by his handlers at the National Public Order Intelligence Unit (NPOIU). The new evidence suggests it was down to the CPS.

 http://www.guardian.co.uk/environment/2011/jun/07/mark-kennedy-surveillance-tapes-cps