The UK is working to come up with a trade agreement with the European Union and is facing a rapidly approaching a deadline before a mandated withdrawal from the economic bloc. In the event that there is no agreement, the country could face a range of consequences, including higher mobile roaming charges for British users, according to a memo from the UK’s Department of Digital, Culture, Media and Sport.

The UK has until March 29th, 2019 to leave the EU — a process that has left Prime Minister Theresa May’s government scrambling to put together an exit agreement that will oversee the country’s economic ties with its neighbors. That isn’t going well, and if the UK and EU parliaments don’t ratify any agreement that comes up, the UK will be left “crashing” out of the EU, with potentially disastrous consequences. Leaving the EU would also mean that the UK wouldn’t be able to enforce EU regulations, such as its abolition of mobile roaming charges for customers, which was approved in 2015 and which went into effect in 2017.

The UK’s Department for Digital, Culture, Media and Sport issued a memo (via TotalTelecom) outlining some of the issues that customers would face in the event of a no-deal Brexit. The 2015 regulation lays out that customers can’t be charged more while traveling elsewhere in the EU, and requires mobile operators to notify customers when they’re reaching the limits to their data allowances. If the UK crashes out of the EU, “the requirements on UK mobile operators to guarantee surcharge-free roaming for customers in the EU are inoperable after exit,” says the memo, because the UK would no longer be part of the EU regulatory structure. It warns that the “costs of regulating retail roaming charges without harmonised wholesale charges may lead to roaming becoming unaffordable to operators.” That, in turn, could lead to higher prices for consumers with the reimplementation of roaming charges, or of roaming being removed from some subscriber packages.

The memo also lays out that the UK will implement new rules that will require operators to continue to inform UK subscribers users when they’re using up their data, and limiting charges to £45 in the event that they go over their limits.

The Guardian reports that Culture Secretary confirmed that the government wouldn’t be able to enforce EU regulations, and that the decision as to whether or not roaming charges would be implemented would be up to individual carriers, and said said carriers “have already said they have no current plans to change their approach to mobile roaming after the [UK] leaves the EU.” But, Shadow Culture Secretary Tom Watson says that those assurances from the carriers don’t go far enough. “The reason the EU introduced free roaming in the first place is because the telecoms companies could not be trusted could not be trusted to give consumers a fair deal.”