Aircraft with say 300 people on board aimed at stadium with about 80,000 capacity.
Bit of a no brainer to say bringing it down anywhere in suburban London except a football stadium would be a least worse option at least on the collateral damage front ?
There's an old 70's book called SAM7 by Richard Cox about the effect of an airliner being brought down in central London. Cannot imagine casualties in the suburbs would be near 80,000 though, but I have no idea really.