The internet has become the fastest-growing advertising medium in the country, accounting for nearly 5 per cent of spending - a greater share than radio or cinema. The rise has been fuelled by the growing number of consumers with broadband web connections and the popularity of search engines such as Google. Advertising companies such as WPP benefit because they can charge more lucrative fees for helping clients navigate the complex world of the web. "Where there is great fragmentation and lots of service providers, margins are really strong," said Lorna Tilbian, Numis Securities analyst.

Internet advertising spending hit £552m last year, passing radio spending, according to Zenith-Optimedia. More money is being spent for advertising on search sites than at cinemas. The internet accounts for a bigger percentage of advertising spending in the UK than in most big countries in the rest of Europe, reflecting the dominance of English on the worldwide web.