The EU has started to clamp down on websites offering mobile phone services after more than half were found to be in breach of EU consumer laws.

Following hundreds of complaints from consumers across Europe, the European Commission launched an investigation last month.

From the 2-9 June, enforcement agencies in 27 EU member states, Norway and Iceland investigated 558 websites to see how they complied with the Unfair Commercial Practices Directive, the Distance Selling Directive and the E-commerce Directive.

EU consumer commissioner Meglena Kuneva said: ”Far too many people are falling victim to costly surprises from mysterious charges, fees and ringtone subscriptions they learn about for the first time when they see their mobile phone bill."

The targeted and coordinated check found various and multiple irregularities in most sites, with six in ten presenting misleading information and 466 sites needing further investigation.

Of the 43 UK websites checked by the Office of Fair Trading, nine in ten were found to need further investigation. Five were potential cross-border cases – when the business, consumer and enforcement agency are not all based in the UK.

Further action will now be taken against eight in ten of the 558 sites. Companies will be contacted by the national authorities and asked to clarify or correct problems identified. Failure to do so can result in legal action leading to fines or closure of their websites.

For cross-border cases, national authorities will work with colleagues from other EU authorities. The UK’s premium rate regulator Phonepayplus has already said it will close down companies that fail to make it easy for consumers to opt out of subscription services.

Authorities are asked to report back on their progress in the first half of 2009.