Channel tunnel operator Eurotunnel is being banned from operating ferry services from Dover amid fears it could use its dominance of cross-Channel transport to hike prices.
The Competition Commission said Eurotunnel's MyFerryLink venture saw it control more than half of the cross-Channel market and said it needed to take action to protect consumers.
Eurotunnel launched MyFerryLink last August with services between Dover and Calais after it snapped up three boats from collapsed operator SeaFrance.
But the commission said it believed Eurotunnel only bought the boats to prevent ferry group DFDS/LD from buying them at a cut price and driving down prices for passengers.
It also said it feared one of the current ferry operators was likely to quit in the short tem, which could hand Eurotunnel an even bigger share of the market.