A further element one needs to add in is that while no credible evidence has been presented in the British media whatsoever that Lugovoi was an FSB agent, his close relationship with Berezovsky's long-term business partner Arkadi `Badri' Patarkatsishvili has been ignored.  The comments on this at the beginning and end of the press conference in which Lugovoi responded to the CPS request for his extradition are likely to be critical to understanding what happened.

At the end of the initial European Tribune discussion, a commenter pointed to the link between Lugovoi and Patarkatsishvili - and also to the latter's role in the `Rose Revolution' in his native Georgia.  But by late 2006, while Berezovsky was still very actively championing `colour revolutions', that in Georgia had blown up in Patarkatsishvili's face, as his relations with Saakashvili had collapsed.  

We also know that Putin had attempted to split the partners when he and Berezovsky fell out.  It may well be the attempt was renewed, exploiting the tensions between Patarkatsishvili and Saakashvili, and Lugovoi was an intermediary.  It is of some moment that Lugovoi is ethnic Russian, and would have been likely to have become vitriolically hostile to the `Rose Revolution' when it emerged that Saakashvili was determined on an all-out challenge to Moscow.

Most traces of polonium can be removed by careful washing and showering.  While one cannot make confident statements until there is more evidence about the radiation trail, it appears eminently likely that the radiation traces that Lugovoi left establish that he was unaware of the properties of polonium.  The British Embassy apparently claimed to Luke Harding of the Guardian that when he visited there on 23 November the chair he sat on was heavily contaminated - although the fact that in one report Harding suggested it had been burned, and in another locked in a room in the Embassy, means that one cannot take this as hard fact.  The inability of British reporters even to remember what they claimed a few months before, let alone what other people have, commonly beggars belief.

If in fact Lugovoi was unaware of the properties of polonium, and there had been the kind of it would not be at all surprising, if indeed there had been the kind of incident or incidents the `suicide or accident' claim implies, to find him ending up genuinely baffled by the question of what Litvinenko might or might not have known.  Another element here is that his repeated suggestion that he and Kovtun were deliberately contaminated to make it possible to incriminate them and the Russian authorities may not actually simply be disinformation.  If in fact Patarkatsishvili was playing a complex double game, which seems at least possible, then Litvinenko might well have regarded Lugovoi as a traitor.

Evidence on these matters is circumstantial, but there is a good deal of it.  There would be a great deal more if journalists in the MSM had bothered to report what Lugovoi said, and follow up the leads he gave.

A preliminary attempt to look at the complexities of the relationship between Patarkatsishvili and Berezovsky, and how Lugovoi might have fitted into the picture, was made in diaries put up in June and July 2009.  These drew very heavily on information from Karon von Gerhke, who was responsible for introducing us to this whole critical - but acutely complex - aspect of the Litvinenko mystery.