More than 70% of UK businesses are preventing their employees from accessing Facebook while at work, according to a survey.

Many are also reportedly warning their staff that use of the social network at work constitutes a sackable offence - City firms Credit Suisse and Dresdner Kleinwort have both banned use of the site.

That’s despite a recent survey showing that two thirds of professionals are using these sites for business networking, 55% of business users go online to share best practice, and 49% do so to seek answers to professional problems.

As well as City firms, the Police, Lloyds TSB and British Gas all have internet filters preventing sites such as Facebook, Bebo and MySpace from being viewed at work, The Telegraph reports.

But with the increasing use of Facebook, LinkedIn and others as a place to build business connections, perhaps some employers are being a little short sighted in their policies.

Further reading:

Facebook closes gap on MySpace