The Litvinenko Inquiry

Part 9 | Chapters 1 to 12 | Who directed the killing?
No radionuclides other than Polonium 210 were identified by gamma counting of
the exhibits supplied by MPS once peaks due to detector background system were
removed. Thus the exhibits also had no fingerprint to distinguish the polonium
210.”
9.67 It follows that the first premise for the ‘fingerprint’ theory that I have set out above is
flawed and must be rejected.
9.68 Turning to the second premise, A1 accepted that the age (and, therefore, the
manufacture date) of a sample of polonium 210 could in principle be calculated by
reference to the lead content in the sample. She referred in this context to the equation
that is used to make this calculation. However, A1 also added a number of important
qualifications.
9.69 First, she explained that due to the form of the equation and the expected uncertainties
of the measurements, it is only possible to use this method to determine the age of
polonium 210 samples up to seven months old. Beyond that period, the changes in
the amount of lead become too small for reliable calculations to be performed.
9.70 Second, A1 said that even for samples still within the first seven months of manufacture,
this process cannot provide an exact date of manufacture. Rather, she explained,
the process can only be relied upon to differentiate between samples manufactured
at least 13 or 14 days apart. As A1 explained in her report, it followed that: “if two
batches of Polonium 210 were purified on two consecutive days or even ten days
apart this could not be differentiated by analysis of Lead 206”. 24
9.71 Turning from the limits of this process in theory to its limits in practice, A1 stated that
most of the exhibits in the present case were not suitable for age dating in any event
because they had been heated and/or cleaned after the date of contamination, which
would have rendered the dating process unreliable.
9.72 In summary, the claims made about the ‘fingerprint’ theory in the passage from Death
of a Dissident that I have quoted above are not supported by the expert scientific
evidence that I have heard. The analysis conducted at AWE does not support the
assertion that all commercially produced batches of polonium 210 have characteristic
impurities, and although there is a process by which such samples can be aged by
reference to their lead content, the process is far from precise and in any event the
samples in this case had not been sufficiently well preserved to enable meaningful
calculations to be made.
The Potemkin evidence
9.73 This issue arises from evidence given by Mr Goldfarb about information and documents
that he received in unusual circumstances from a man calling himself Alexei Potemkin.
9.74 Mr Goldfarb provided lengthy written evidence about this issue and also answered
some questions about it when he gave oral evidence. 25 The tale that Mr Goldfarb
related was a complicated one, and I will summarise it as briefly as I can.
9.75 Mr Goldfarb explained that he had first been contacted by Mr Potemkin in June
2010, by email. Thereafter they had exchanged several emails. In the first instance,
24
INQ016403 (page 31)
25
INQ018946; INQ017548 (pages 8-9); Goldfarb 26/125-127
219