You can see an electric bike with a Bionx shaped battery at 30 seconds in the BBC video - a rather upright riding position obviously helped by the motor.
I have done a bit of goggling on the winner. It turns out he is a 54 year old
lawyer, who gives lectures on electric bikes taking the puff out of cycling! I wonder what he says about the legal aspects of using his bike on the road.
It looks like he has converyed a bike using one of the illegal Bionx kits - he links the
BionX electric bike motor systems web page to explain what he has done.
As a keen unassisted cyclist before going electric at his 50th birthday, he is doubtless still pretty fit. But for the reasons Flecc gives this was highly unlikelyto have been a legal ride into Oxford, stopping at red lights and using a ebike in a legal configuration.