8 June 2011 Last updated at 11:21 ET

CPS probes non-disclosure claims in power station case

Undercover officer Mark Kennedy denied he "went rogue" while working with the activists

The Crown Prosecution Service (CPS) is investigating claims that material was withheld in the case of six activists accused of planning to shut down a Nottinghamshire power station in 2009.

Prosecutors discontinued the case in January, saying it had been undermined by "previously unavailable material".

The CPS says it is now examining claims that prosecutors had access to the information for longer than disclosed.

An undercover officer was involved in the police case against the activists.

Full and formal inquiry

In a blog posted after the Guardian published an article on the claims on Tuesday, the CPS confirmed it had launched a "full and formal inquiry".

It said Deputy Chief Crown Prosecutor for CPS North East Chris Enzor had been put in charge of the inquiry in April.

The original police investigation into the case took at least two years and Mr Enzor's review of the evidence was likely to take "some time", the CPS said.

"The CPS will share the findings of this inquiry with the IPCC and Nottinghamshire Police, and will also make a public statement, in line with our policy to be accountable to the public and transparent in our work."

The case

The six activists were originally charged with conspiring to shut down the Ratcliffe-on-Soar power station in Nottingham in 2009.

The collapsed case

7 January 2011: CPS announces it is discontinuing the case

10 January: CPS offers no evidence against the six activists

21 March: CPS completes internal review of the case

23 March: CPS receives letter from Deputy Chief Constable Chris Eyre

24 March: CPS review extended

Source: Crown Prosecution Service

Their trial was due to start in January 2011 but the prosecution subsequently discontinued the case against them.

The decision came amid reports that Pc Mark Kennedy, who had infiltrated environmental groups, had changed sides and had offered to help the defence. Mr Kennedy later denied he "went rogue" - but admitted questioning his role.

Announcing the decision to discontinue the case, a CPS spokeswoman said that "previously unavailable information that significantly undermined the prosecution's case" had come to light on 5 January.

"In light of this information, the Crown Prosecution Service reviewed the case and decided there was no longer sufficient evidence for a realistic prospect of conviction," she said.

But on Tuesday the CPS said that, on 23 March, it had received a letter containing "claims that CPS had earlier sight of material in question".

It said the letter, dated 17 March, had been sent by Nottingham Deputy Chief Constable Chris Eyre and was received by the CPS on 23 March - two days after the completion of an internal review into the prosecution's disclosure of material.

The CPS recommended a fuller inquiry in light of his allegations and appointed Mr Enzor to investigate.

Appeal

After the collapse of the case in January, the CPS asked Clare Montgomery QC to advise on the safety of the convictions of the 20 activists in an earlier case.

The activists had been convicted in December 2010 of conspiracy to commit aggravated trespass at the Nottinghamshire power station the year before.

On the basis of Ms Montgomery's review, Director of Public Prosecutions Kier Starmer QC said he believed the Court of Appeal should look into the safety of the convictions.

He advised the 20 activists to appeal.

Those convicted were among more than 100 people arrested in Sneinton, Nottingham, in April 2009.