Within an hour of the news breaking, the Tories purchased the adword and recorded a special webcast. The result: anyone typing James Purnell's name into Google saw an ad stating: 'Purnell Quits: Labour is falling apart. Watch David Cameron's reaction.' Clicking the link led to the Tory website and a video of leader David Cameron calling for an election.

Diffusion director Ivan Ristic commended the Tories.

He said : 'The Tories are winning the Google battle and leading the way in the use of search engines as a part of political campaigning.

'Journalists, bloggers and political enthusiasts look to Google when a news story breaks. And Google Adwords is a targeted, rapid and cost- effective way to influence and shape opinion, media coverage and blog commentary triggered by a major politi- cal event.'