Consumer group MoneySavingExpert.com, led by consumer rights campaigner Mr Lewis, has called on telecoms regulator Ofcom and the government to tighten rules after some consumer protection measures expire after Brexit. In a new report, Mr Lewis warned that because a number of legal obligations for operators around roaming ended on June 30 this year, companies no longer need to text customers with billing details when they start roaming . apply a monthly cap on data roaming charges; or provide protection against inadvertent roaming. Some of the UK’s biggest networks have reintroduced data roaming charges in Europe after the UK left the EU. Mr Lewis said mobile operators could not be trusted to self-regulate, as some operators had promised not to bring back roaming charges after Brexit but were now doing so, and called on the government and regulators to step in. “I don’t believe mobile phone companies will self-regulate. When we left the EU they promised not to bring back European roaming charges… yet most of the big networks broke that promise,” he said. “So our report calls on Ofcom not to trust voluntary promises – we need to bring back formal, mandatory consumer protection.” The MSE report also raised concerns about different providers using different definitions of “day” roaming, which it said created confusion and risked unexpected costs. The report said that while some operators define the day as 24 hours from first use, others define it as anything up to 11.59pm in the UK on the same day, which the consumer group claims means someone who signs up on 23 :58 would only take one minute of data before you have to pay again. Martin Lewis (pictured with his wife Lara Lewington) was awarded a CBE earlier this year (PA wire) He says this is not explained in the arrival texts. “We need to ban the daily roaming charge that is charged for use ‘until 11.59pm’ without even mentioning in which time zone,” Mr Lewis said. Instead, we recommend that all providers define a roaming ‘day’ as a period of 24 hours from first use, explain this clearly in the arrival text and notify customers at least one hour before daily charges end.”