Banks have reacted angrily to claims by Which? Money that many savings providers fail to keep their customers informed about important changes to interest rates on their accounts.

The consumer body claimed that only four of the 12 banks or building societies investigated guarantee to personally inform their customers of all savings rate changes, with most using on adverts in newspapers or the chance of people popping into a branch to announce smaller rate cuts and rises.

Which? claimed that only Cheltenham & Gloucester, First Direct, Co-op and ING Direct promise to personally notify their customers – by either email or letter – of all cuts in interest rates on their accounts.

Which? chief executive Peter Vicary-Smith said: “Our rigorous research shows that outdated and inconvenient methods of notice on interest rate changes are keeping savers in the dark for longer