Stena Line has banned Glasgow Rangers supporters from travelling as foot passengers to football games because of the "loutish" behaviour of a number of fans travelling from Stranraer to Belfast last Saturday.
According to Stena, the trouble broke out when some of the 500 Rangers fans returning from Saturday's Old Firm game against Celtic began to sing sectarian songs and chant sectarian insults.
"On this occasion, those involved in the singing were travelling as foot passengers, which means it is difficult to identify exactly who the culprits are. Therefore, with immediate effect, Stena Line will not carry Rangers groups travelling as foot passengers," a spokesman said yesterday.
"We will, however, continue to carry Rangers supporter groups travelling in cars and coaches, as those that travel with us on a regular basis behave very responsibly. The Rangers fans involved in Saturday night's behaviour were in the minority."
About 200 of the 500 Rangers supporters who travel weekly to games in Scotland go as foot passengers. Stena said the ferries had been able to accommodate Rangers supporters travelling to last night's UEFA Champions League home qualifying game because potential foot passengers had made arrangements to travel by coach or car.
Jim McGreevey, whose mother was on board Saturday's ferry, said she had been terrified by the sectarian behaviour.
He told BBC Radio Ulster's Stephen Nolan Show: "The supporters, they weren't even singing football songs, it was about killing Catholics, and named Catholics that have been shot dead."
Rangers defeated Celtic 3-1 in Saturday's game, a result that triggered sectarian violence in north and east Belfast.
A Stena spokesman said yesterday: "When travelling with Stena Line, football fans and supporters' clubs must adhere to strict conditions of carriage which have been designed in partnership with the football clubs and supporters' bodies to ensure that both supporters and the rest of our guests enjoy their experience on board."
He added: "The same conditions of carriage, which are distributed in advance of travel, will apply to any other football supporters, regardless of what team they support, and indeed any other group of passengers, should they misbehave on board in future."