8 miles each way .. 30 mins through central london though with 6000 sets of traffic lights.
That's only 16mph, if you get lucky on the lights that seems plausible.
errr, yes, if I got lucky on every single set of lights for 8 miles in london I'd be buying a few lottery tickets too.
factoring in even 5mins for light stops you average 19mph. still not realistic imo given stop/start/slowing/weaving buses/cabs….
agreed possible, but you'd prob die within a few attempts either getting hit by a bus/tourist/fixie hipster not paying attention