The cross-channel rail company Eurostar told passengers not to turn up at the London terminus, because all trains to Paris and Brussels were full for the day.
With Christmas looming Eurostar is still trying to clear the backlog of several thousand passengers, stranded after services were paralysed for three days at the weekend by train failures.
The company said it was operating at two-thirds capacity on the second day of the resumed service.
Police turned out in force at St Pancras station in London as long queues of hopeful travellers descended into chaos, spilling out of the station and onto the street.
Tempers began to fray amid claims that Eurostar was allowing passengers with current tickets to jump the queue ahead of those who had been waiting to travel for days.
Passengers with tickets dated Tuesday said they believed they would be given priority.
Elderly travellers or those with young children were ushered to the head of the queue, but once more Eurostar was being accused of supplying confusing information at best, and at worst, no information at all.