The consumer champion surveyed more than 4,500 members of the public on their opinions of their current account providers, and found a trio of challenger banks were the most highly rated by customers.

Starling Bank, Monzo and First Direct topped Which?’s customer score table, with users ranking the brands highly for their customer service, application process, communication and transparency of charges.

Starling Bank and First Direct were also named Which? Recommended Providers.

All of the biggest banks finished outside the survey’s top six, with RBS (61%), TSB and Santander (both 63%) languishing in the bottom third of the table.

RBS holds this year’s unwanted record for the most two-star ratings in the survey with customers criticising its telephone service, account benefits, complaints handling, branch service and overall customer service.

The bank fared better for online services, achieving four stars, while its mobile app got three stars.

In a separate study by Ipsos Mori in February, RBS was also ranked at the bottom for personal customer satisfaction in the UK and came in at the lowest level yet in its provision of business current accounts.

The Ipsos Mori survey found that just 46% of RBS customers would recommend their personal account provider to friends and family.

Starling Bank finished top of the 24 brands ranked in the Which? survey, achieving a customer score of 88%. Customers praised its “clear and honest communications”, the ease of opening an account and using the app, as well as speedy responses from its “excellent” customer service team.

Monzo received the second highest customer score of 82%. However, Which? has not formally endorsed the bank with its Which? Recommended Provider status as it has not met key criteria by signing up to the Contingent Reimbursement Model (CRM) voluntary code, where banks refund blameless victims of authorised push payment (APP) fraud.

First Direct slipped from first to third place this year but achieved a score of 79%, earning five stars for customer service, complaints handling, online service and its mobile banking app.

Another bank that received Which? Recommended Provider status was M&S Bank, with a customer score of 77%. It also earned five stars for online service.

Jenny Ross, Which? Money editor, said: “The leading challenger banks have cemented their position ahead of many of the UK’s biggest banking brands in terms of customer satisfaction, showing that innovation and modern ideas are shaking up the market. However, it’s still good service that is truly valued by customers.

“Our research shows a clear gap between the best and worst providers and should encourage customers unhappy with their service to switch banks, as it’s never been easier.

“It’s vital that banks sign up to the industry code to reimburse blameless victims of authorised push payment (APP) fraud. Current account providers that haven’t will not be named Which? Recommended Providers.”