But going public with an accusation like this (and another one that the Russians scouted out another London-based critic, Boris Berezovsky) is another matter and it will raise the diplomatic temperature.
Whether the comments were timed deliberately or whether they just came out in the course of a conversation with the BBC journalist is not clear. Sometimes, these revelations are not the result of a careful decision but just emerge and have all kinds of unexpected repercussions.
It is a reminder that all is certainly not well in the relationship between Russia and Britain and, beyond that, between Russia and the West in general.
It will dash any hopes that the meeting at the G8 in Japan between the two prime ministers, Gordon Brown and Dmitry Medvedev, might have started a new chapter.
The talks were in any case, according to a Russian official, "sharp" at times as Mr Brown raised the various issues clouding the relationship - the outstanding extradition request, the restrictions on the British Council and the Russian manoeuvres against BP [British Petroleum].
Did President Bush raise any substantive questions with Medvedev when they met with one another? Or did they have other things to talk about? Or is he operating under the assumption that Putin is still running Russia?
I think that's the safest assumption of all.