UK banks now publish the number of outages under a voluntary scheme overseen by the Financial Conduct Authority (FCA) and the data shows that most major banks suffer at least one shutdown per month.

The regulator had implemented the scheme to make it easier for customers to compare banks and their quality of service. Banks now show how long it takes to open an account, replace a lost or stolen card and arrange overdrafts.

The shutdown figures cover the nine months to the end of last year, and BBC analysis showed most major High Street banks suffered more than ten shutdowns between April and December.

Barclays suffered the highest number of incidents – 41 in nine months – but said that most were minor and the bank’s service was designed to allow customers to use other channels, such as branches and telephone banking when problems occurred.

Lloyds has had problems over the past month. Customers reported problems accessing their banking in mid-Febriary, less than a month after the group struggled with payments processing across all three of its brands with around 400,000 transactions delayed.

Larger banks tend to be more vulnerable to outages because they have complex legacy systems. Attempts to upgrade these systems can create problems, as Paul Pester, CEO at TSB found. He had to step down after the botched migration of customers to a new banking platform in April of last year.

The banks’ representative body, UK Finance, told the BBC that its members invested billions of pounds in ensuring IT and human systems were “robust and secure”.

Also, the data showed the number of shutdowns does not necessarily translate to poor customer satisfaction. Barclays, despite recording the highest number of incidents, was ranked joint fifth for overall satisfaction in a survey of 16,000 banking customers. Metro Bank and First Direct were top.