I found the following elsewhere:
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=comm...
http://preview.tinyurl.com/2p2tgy
"Sources close to the investigation also tell The DAILY that British
Airways engineers have been collecting fuel samples from every flight
emanating from China. The sample collection, plus comments from the
AAIB indicating the aircraft had "adequate" fuel remaining on board at
the time of the crash, is believed to point toward suspicions of a
heavier-than-fuel contaminant being present. Theories propounded by
crew include the possible presence of water in the tanks that, having
become frozen during the intense cold-soak period of the flight,
partially melted and formed a slush that could have partially blocked
the fuel lines.
Sources also tell The DAILY that upper air temperatures over Russia
and northern Europe were extremely cold on the day of the accident.
Information from other crews coming from Asia on Jan. 17 encountered
extremely low temperatures in the -70 to -75 degrees C. range,
resulting in fuel temperatures dipping into the -40s. European upper
air temperatures also indicate the last 6.5 hours of the inbound China
flight would have been flown at an outside air temperature of -60 deg.
C. or lower. Although this would have resulted in fuel temperatures on
approach in the -35 degrees C range, this would not normally
constitute a problem unless, potentially, contaminants were present."
And it's been said (not by me) that "Sources close to the investigation" means a leak from the AAIB investigation. True? Likely? Or just yet more speculation & rumour-mongering?