The European Commission has said it will take 'concrete action' against mobile phone operators in the UK and Germany for what it believes are excessive roaming charges.

"The situation is most serious in Germany and the UK, but that does not rule out action against operators in other countries too," said Michael Tscherny, spokesman on competition issues at the Commission.

The action is likely to mean the formal opening of lawsuits against the six operators competing in the UK market and four German operators, Tscherny said. "We will take action after the August recess," he added.

Roaming fees are charged to users when they use their mobiles outside the geographic area covered by their provider, normally when they travel abroad.

A year ago the Commission conducted dawn raids on operators in the UK, including BT and Vodafone, and Deutsche Telekom in Germany. But Tscherny said that the competition authority would not have to carry out surprise visits to other operators in order to open other such cases.

EU antitrust lawsuits begin when the Commission sends a so-called statement of objection to the companies involved, outlining accusations. Cases then usually take between 12 months and two years to conclude.

The Commission's tough line on roaming charges has come under some criticism from the industry. "Roaming charges are one of the few revenue sources these companies can rely on to finance the enormous infrastructure expenses incurred by the preparation for 3G [third generation] mobile telephony," said one lawyer close to the telco industry who requested anonymity.

"The situation is bad enough for mobile operators without added pressure from the Commission. I hope it will be pragmatic when it decides what to do in these cases," the lawyer said.