As millions start their Christmas shopping online, there's a warning that consumers may need to have a mobile phone, and a decent signal, to make sure their transactions go through. UK banks are starting to introduce a new layer of security, involving passwords sent to your mobile phone. That could be a problem for hundreds of thousands of householders without a mobile, or no proper signal. Now banks are being urged to find other ways to check a customer's identity. The new rules are part of an EU directive - already adopted by the UK - which is due to come into force by September 2019. But critics say many people are likely to be inconvenienced. "Banks are not yet great at looking after people at the margins - because they're disabled, or because they live with no mobile coverage," said James Daley, the managing director of Fairer Finance.