Metropolitan Police website contains a statement and there are links to more detailed documents. See also The Independent 28th April.
Blair Peach was an "anti-racism" campaigner who opposed a National Front March through Southall. The Home Secretary [Mr (later Lord) Merlyn Rees] did not act to prevent the march even though there was massive objection to it. Even at the time, the policing of this event raised many allegations of police officers using excessive force. It appears that 14 witnesses claimed to have a seen a Police Officer strike Blair Peach and there was no other evidence to suggest how he came by his injury from which he died. Nevertheless, politicians and the media generally took the stance that the Police acted properly.
It would appear that investigations are now over and that it is highly unlikely that prosecutions will be brought. The Metropolitan Police Commissioner says it is a "matter of deep regret" and that it "reflects the way Policing was rather than is". It would be a massive understatement to say that many people will be wondering whether some things have really altered all that much - see, for example, The Guardian 28th April. Nevertheless, the publication of the reports ought to be welcomed as a small step toward the achievement of that elusive and indefinable but necessary concept of "Justice".
See also INQUEST and DKRenton.
Also London Evening Standard 28th April - Yasmin Alibhai-Brown.