Microsoft is giving users greater control over what the company does with information it gathers about their online behaviour.

According to an updated privacy policy unveiled today, the software giant will let its customers decline advertisements tailored to their web surfing habits. The company will also anonymise cookies – which contain information about internet use - after 18 months.

'What's really different with our offering is what we mean by anonymisation. Anonymous should mean anonymous,' said Brendon Lynch, director of privacy strategy at Microsoft.

The move comes as internet rival Google faces increasing pressure from Brussels to cut the time it holds users' search information. The EU working party on Data Protection wants the firm to go further than its current offer of a two-year lifespan for its cookies – a measure that would only be effective if the user never visited Google again.

The Federal Trade Commission in the US is currently investigating claims that Google's planned $3.1bn (£1.5bn) purchase of DoubleClick gives it access to too much information about internet users' searching and browsing habits.