My understanding was that some requests could't be met because CRU didn't have the authority to release the data requested, and the requests were made again and again inspite of this.
This is the text of the ICO statement:
Norfolk Police are investigating how private emails have become public. The Information Commissioner's Office is assisting the police investigation with advice on data protection and freedom of information. The emails which are now public reveal that Mr Holland's requests under the Freedom of Information Act were not dealt with as they should have been under the legislation. Section 77 of the Freedom of Information Act makes it an offence for public authorities to act so as to prevent intentionally the disclosure of requested information. Mr Holland's FOI requests were submitted in 2007/8, but it has only recently come to light that they were not dealt with in accordance with the Act. The legislation requires action within six months of the offence taking place, so by the time the action taken came to light the opportunity to consider a prosecution was long gone. The ICO is gathering evidence from this and other time-barred cases to support the case for a change in the law. It is important to note that the ICO enforces the law as it stands - we do not make it. It is for government and Parliament to consider whether this aspect of the legislation should be strengthened to deter this type of activity in future. We will be advising the University about the importance of effective records management and their legal obligations in respect of future requests for information. We will also be studying the investigation reports (by Sir Muir Russell and Norfolk Police), and we will then consider what regulatory action, if any, should then be taken under the Data Protection Act. (2)It's worth pointing out that the commissioner seems to have based his opinion on the content of the emails themselves, ("The emails which are now public reveal that Mr Holland's requests under the Freedom of Information Act were not dealt with as they should have been under the legislation.") rather than by actually speaking to the people involved and asking whythe request wasn't granted. If that's the case, it's a bit odd.
It might also be an administrative issue - instead of informing him that his request had been declined and why, he was simply told to piss off or ignored outright. Dunno, based on the statement. but it certainly doesn't help. If CRU weren't dealing with legitimate requests properly, then they should be sanctioned for it, because they've given the wingnuts a fantastic opportunity to shriek and gibber about something other thanthe science - which is their only really effective strategy.
It might be a case that the scientists developed a 'bunker mentality' because of the continual misrepresentation and twisting of data and work by the deniers, but whatever the reason, it is a very poor show by CRU if they were withholding data they should have release.
1 - "Climategate university 'breached data laws'," by by catherine Brahic. Published on Short Scharp Science: a science news blog from new Scientist, 28th of January, 2009. (http://www.newscientist.com/blogs/shortsharpscience/2010/01/climate-scientist-breached-dat.html)
2 - Text is reproduced in the blog post linked above.