Re: Ugh, more nonsense
Your farting fixation aside, what the London start-up scene has going for it is that it's willing to take more risks (hence more failures), moves more quickly, and is better at self-promotion. Where it falls down are the countless start-ups that are aping existing successful ideas, but in different niche markets, or that are basically solving a problem nobody has - a problem not just confined to London companies.
On the other hand, the Cambridge scene has some tremendously intelligent academics attempting to commercialise their research. However, to generalise wildly, they're too risk-averse, slow-moving and mostly unable to articulate simply the benefits of their product to their markets. Hence very few companies succeed globally, despite the strength of their product. Being called "the best-kept secret on the internet" isn't meant to be a badge of honour. And they're equally susceptible to creating products that solve problems nobody has.
Now if some bright spark can figure out a way to combine the best aspects of these two technological hotbeds, then we're looking at a far more interesting proposition. Plus they have the advantage of being comparatively close to each other.
[I write from experience of working in both Cambridge and London software companies - as I've no direct experience of Silicon Glen or M3 corridor, I've chosen not to comment either way]