Football

You're missing the point about speciation. If no one else breeds with these pallid East London types, then eventually they will become their own species. Far removed from human kind.

Think: Genetic bottlenecks. Usually in the form of mountains.

Eventually yes they would. but it would take a fuck of a long time before they became unmateable with humans as we know them.
It's possible that if Neanderthals were alive today, we could successfully mate with them and that's going back hundreds of thousands of years. Though they are in the same genus.
West Ham fans. Hmm it's a different ball game. Similar to those creatures in The Descent. I wouldn't fancy my chances 'hanging out the back of' one of them