Last night was the deadline for all European mobile phone network operators to take the first steps in introducing the EU's compulsory Eurotariff.
The European Commission, having "faced resistance" from certain carriers has stated today that a list of non-compliant companies will be posted online by the end of the week.
A European Commission spokesman, speaking at a news conference said: "Today is a very important day".
"According to the roaming regulation, all roaming customers in the European Union should be given the opportunity by 30th July, 2007, to opt deliberately for the new Eurotariff."
The rollout timetable states that by the end of July, the operators must have contacted all of their customers to inform them of their tariff options and explain when the new Eurotariff will be made available.
By the end of August they should introduce the new tariff, both for new and existing customers.
By the end of September, they should transfer all customers to the Eurotariff automatically, except for those customers who have explicitly chosen another tariff.
More from the EU: "This is not a recommendation, it's a regulation. So it's directly applicable law".