'Silicon Roundabout' was what Matt Biddulph, of social network Dopplr, sarcastically dubbed the drab Old Street and City Road junction in July 2008. London's fume-filled, concrete roundabout may not have had the glamour or scale of California's Silicon Valley, but the label helped pinpoint a new generation of tech talent that included music site Last.fm and printworks Moo.com.

Two and a half years later and the joke has worn thin. Comparisons with the sun-soaked US technology scene no longer feel relevant to a startup community that's thriving in London and in pockets of energetic industry across the UK and Europe.