Last night BBC Radio 4 broadcast a documentary about the Climategate affair, in which thousands of documents mysteriously obtained from a computer server at the University of East Anglia were released onto the internet in 2009.
The material belonged to some of the world's leading climate scientists and caused them difficulty just before the major United Nations Copenhagen summit on climate change.
Called Climategate Revisited, the programme examined the impact of the ensuing controversy about the conduct of climate science on public opinion, media reporting and the scientific community. It was produced by me.
Making a radio documentary is always an exercise in trying to squeeze a quart into a pint pot. Your researches invariably collect more information and recordings than it is possible to fit into the allocated slot.
Since in this case some unbroadcast material comes from a freedom of information request, I thought I should write about it here. So this contains some additional information about the police inquiry beyond what was in the programme.
Norfolk police investigated the possible criminal hacking of the university's computer system, until they announced in July they were abandoning the operation. Proceedings under the relevant part of the Computer Misuse Act have to be brought within three years. Since they had not yet identified a suspect, they said there was no prospect of a prosecution within the time limit.
I submitted an FOI request for some of the files compiled during their inquiry, called Operation Cabin. The first point I should make about their response is that they released much more information than in any previous case in my experience where the police have been asked about such a recent investigation. I did not get all the material I requested, but they did send a number of interesting documents.
During the operation some people queried whether the Norfolk force had sufficient expertise to run a specialist technical cybercrime inquiry. This concern is reinforced by the files released.
The operation was reviewed by a senior counter-terrorism officer who concluded that "there are national units both in policing and with partner agencies that have specialist knowledge and skills that would have added value to the inquiry."
He did praise the Norfolk investigators for their "impressive" commitment, adding that most UK police forces have little specialist capability in this arena.
The Norfolk investigation was led by Detective Superintendent Julian Gregory, who has since retired. He told us: "We sought assistance from a number of quarters and we probably didn't get everything we wanted."
"If you look at national assets, they've all got their own workloads," he said. "We got the technical support we needed from counter-terrorist command, but other units had their own priorities."
Another document shows that the police decided not to make a media appeal for information to assist the investigation during the Copenhagen climate summit (known as COP15), because "with COP15 still underway in Copenhagen raising awareness still further may have an negative impact on the conference".
Some may be surprised that the police would allow these apparently political considerations to affect their conduct of an investigation.
Former Det Supt Gregory explained that "we didn't want to create even more speculation around that conference". But he also stated that more significant was a practical consideration, a feeling that the police infrastructure might not be able to cope with the deluge of calls which could result.
Other files released show that the University of East Anglia was represented on the Gold Group which oversaw the strategy of the investigation. Meetings were attended by Brian Summers, the UEA Registrar.
I was initially surprised to discover this, since one hypothesis the police had to investigate was whether it could have been an "inside job" in which a UEA employee had leaked the material, acting as a kind of whistleblower. But I gather from other police sources I have talked to since that this is not necessarily unusual.
"We'd often engage the people we think need to be involved in a Gold Group," former Det Supt Gregory told us. "Presence at the meeting doesn't give any undue influence or anything untoward like that. It was appropriate that they were engaged and we understood their perspective as we undertook our work."
But he added there were constraints on what he said at the Gold meetings. "Where appropriate I would not enlarge on certain lines of enquiry. I would deal with those in a more private context. I never felt compromised as the senior investigator."
The disclosures also reveal how the police worked their way through certain websites on which Climategate had been discussed, printing off and filing away, for example, a list of staff at the Taxpayers' Alliance.
However, there was other information which the Norfolk police refused to release, such as the identity of those countries from which they sought help with the investigation. They argued that this could damage future international cooperation.
These are some of the documents released by the police: