Introduced in September 2013, the £750 million Cass was designed to make it easier and quicker for Brits to move their bank provider, boosting competition. Celebrating its third birthday, Bacs, which runs the service, says that in its three years, it has seen 3,240,640 successful switches - including 73,899 small business accounts - and reports a seven day switching success rate of 99.7%.

However, whether this is enough to placate regulators is questionable. Last March, disappointed in takeup, awareness and confidence in the system, the Financial Conduct Authority stepped in calling for marketing campaigns.

With the threat of an expensive move to full account portability hanging over their heads, banks and building societies stumped several million pounds for marketing. The latest set of ads will begin this weekend, while a new website dedicated to the service is also being launched.

With increased competition the government's main driver for making account switching easier, Bacs says that during the last three years there have also been 150 "enhancements" to UK personal current accounts, while the number of banking providers offering the service has risen from 33 to 43.

Anne Pieckielon, director, product and strategy, Bacs, says: "Since the Current Account Switch Service was launched, we’ve worked hard to keep pace with changing needs, collaborating across the industry and with government and regulators - such as the Competition and Markets Authority - to provide a world class switching service for individual customers, and smaller businesses and charities."