Länk - Mer om Poloniummordet i London

"No individual could do this," said John Large, an independent nuclear consultant. "What you are talking about is the creation of a very clever little device, a designer poison pill, possibly created by nanotechnology. Without nanotechnology you would be talking about a fairly big pill, a pea-sized pill. Either way you are looking at intricate technology which is beyond the means and designs of a hired assassin without a state sponsor." He said the likely poison pill that killed Mr Litvinenko would have to have been manufactured in a special laboratory over two or three weeks and then used very quickly - possibly within 28 days - because the half-life of the isotope polonium is only 138 days.