The radioactive traces being found on the the planes doesn't ring true to me, unless it was deliberately planted there (by who, and why?). Even if Russian secret agents did bring Polonium 210 into the UK on flights from Moscow in order to assasinate Litvinenko, you would think they would keep it very well contained.

As with anything in the mainstream media, there's something about this story that smells funny.

UK experts probing the death of former Russian spy Alexander Litvinenko have found traces of radioactivity at 12 locations, the home secretary has said.

Radioactive traces have been found on two planes and a third is awaiting checks. British Airways is contacting 33,000 passengers from 221 flights.

http://news.bbc.co.uk/1/hi/uk/6159927.stm

Not sure how big of a deal the media are making out of this as I don't have access to any TV station or Radio station.  But many of the news sites have it as one of their main stories.

So something has probably been going on - but are the media / government using it as a scare story?  Well there is a great comment that has been added to the BBC news article by a reader: