Customers with 20 major banks including Halifax, Barclays and HSBC are encouraged to note an important phone number to help protect themselves from being taken in by a scam.

Three new banks have signed up for the 159 service, a number for customers to call if they get a suspicious call purportedly from their bank, to be connected to a secure number for their institution.

Revolut, Chase and Modulr are the latest to sign up for the service, joining big names such as NatWest and Nationwide, with…