If you stand on the corner of Regent Street and Wigmore Street in central London, you are within five miles of 164 branches of Starbucks. This is a fact that is liable to provoke sudden dizziness, followed by a deep, soul-corroding fear for the future of humankind, sending you scuttling to your bedroom to throw yourself, sobbing, underneath a pillow - although this won't help much either, since that pillow itself is within five miles of 158 branches of Starbucks, if it's my bedroom you're in, which, now I come to think of it, I hope you aren't.

You can calculate your personal "Starbucks density" on the company's website (Starbucks.com/locator), but be warned: any figure you come up with now will soon be out of date. Yesterday, the company announced a massive UK expansion, focused on London, where it expects to open new outlets at the rate of one a fortnight over the next 10 years.

How many Starbucks is too many? In what seems now like a distant historic era - actually, it was 1999 - the frenzied growth of the US chain became a symbol of expansionist multinational capitalism, all the more insidious because of the way each branch posed as a cosy neighbourhood coffee shop when, in fact, it was driving neighbourhood coffee shops to the wall. (Admittedly, the argument always had more credibility in San Francisco or Seattle than in Britain, where we didn't really have coffee shops in the first place.)

Now there are 530 branches in the UK, but that doesn't mean there isn't still room for aggressive expansion. Starbucks is a long-time practitioner of clustering, whereby the chain opens outlets so close to each other that it ends up cannibalising its own business. At first glance, this doesn't seem to make any business sense. "But that's because they're in it for the long game, which is market share," says Andrew Simms, of the New Economics Foundation, which has published reports condemning the "cloning" of the British high street. In other words, cannibalisation is worth it, if the overall effect is to solidify your position as the first name anyone thinks of when they think of coffee.

You or I might feel that living within five miles of 158 Starbucks is plenty. But look at it from Starbucks' point of view: there are hundreds, maybe even thousands of shops within five miles of my flat that aren't yet branches of Starbucks. Although it is probably only a matter of time.