Eurotunnel faces claims from Brussels that passengers using the Channel Tunnel are being overcharged.
The European Commission said both passengers and freight services are paying over the odds for using the track through the tunnel, which is operated by Eurotunnel.
The Commission called on the British and French governments to look into the pricing structure and to comply with European Union rules against excessive track access charges.
The high prices Eurotunnel charges the train companies get passed onto passengers, it added, claiming that 43% of the Channel Tunnel’s capacity is currently unused.
Commission vice-president Siim Kallas said: “The Channel Tunnel is not being used to its full capacity because of these excessive charges.
“As a result, more freight is being carried on lorries instead of by rail, freight operators and their customers are being over-charged, and passengers are paying over the odds for their tickets. The current regime is also stifling growth in the rail sector.”
Eurotunnel countered by saying its charges are “transparent and not excessive.”
The company said that it has “always sought the development of cross-Channel traffic and concentrates significant resources on this goal”.
It said it believed that only Eurostar is contesting a claimed lack of transparency in 2014 access charges to the tunnel, “finding issue with a contract which it has applied for 19 years”.