EUROPEAN Commission inspectors have made surprise visits to the offices of some cross-Channel ferry operators as part of an investigation into illegal price-fixing practices.

Although the commission stressed that no formal investigation had been launched, it is understood that surprise inspections are a preliminary step in investigations into suspected cartels.

P&O Ferries and Eurotunnel confirmed that their offices had been visited. It is not known whether Hoverspeed, Norfolkline or SeaFrance were also included.

British consumers have complained to the Commission that cross-Channel ferry prices appear to be similar.

In a statement, the Commission said: "The purpose of these inspections is to ascertain whether there is evidence of suspected market-sharing agreements and related illegal practices aimed at foreclosing competition".

Investigators will consider the material they have taken away before deciding whether to launch a formal investigation.