In the past year, UK banks suffered 265 IT shutdowns that prevented customers making payments.
New data from the Financial Conduct Authority (FCA) shows that banks reported the equivalent of five IT glitches a week between October 2018 and September 2019.
Read on to find out how many incidents and security breaches your bank suffered.
The FCA's data tallies the number of 'major operational or security incidents' suffered by banks in the past 12 months.
A major incident classifies as something that affects the ability of a significant number of customers to make transactions using internet, mobile or telephone banking.
In total, 265 incidents were recorded, with problems affecting internet banking the most commonly reported.
Internet banking services suffered 133 shutdowns, compared with 111 with mobile banking and 90 with telephone banking.
Some single incidents may have affected more than one brand. This means the total number ofuniqueincidents may be less than 265.
Royal Bank of Scotland and Santander reported the greatest number of incidents (18 each), followed by Barclays (17) and Tesco Bank (16).
You can find out how your bank compares in the below table.
The FCA publishes its data on IT glitches on a quarterly basis.
In its previous release, covering the 12 months between July 2018 and June 2019, it recorded a total of 228 glitches - 37 fewer than the year to September 2019.
It's hard to compare from previous years, as the FCA has only required banks to publish the information since 2018, following an investigation into the banking sector by the Competition and Markets Authority.
If you're considering opening a new account or switching provider, these figures might set alarm bells ringing.
But while the overall number of shutdowns might sound significant, some singular problems may have been reported in the data several times.
For example, if one IT failure has hit several brands within the same banking group, it may be recorded as an individual case for each bank.
Internet banking is a hot topic at the moment.
The FCA's findings come hot on the heels of TSB being criticised over a major IT meltdown last year that locked two million people out of their accounts.
In an independent report, the law firm Slaughter and May said bosses at the bank made an 'ill-judged' assessment on the readiness of a new banking platform for its five million customers.
It found that the new IT system was 'neither stable nor complete' when it was launched in April 2018, resulting in one of the UK's biggest banking shutdowns and leaving TSB with a £370m bill for customer compensation.
Our 2019 banking customer service survey awarded Which? recommended provider status to four banks - First Direct, Monzo, M&S Bank and Nationwide Building Society.
Our survey, which was based on responses from 4,255 members of the public, gave ratings to banks based various customer service elements, including the account application process, communication complaint handling and in-branch service.
When online banking goes down, you may need to rely on cash, but what if cash no longer exists?
Gareth Shaw, head of money at Which?, said: 'The countless communities across the UK with shockingly low cash machine provision show that measures intended to guarantee access to cash simply don't work.'
Ultimately, we do not think any of the schemes currently in operation will be enough to protect cash access in the UK. That's why we're continuing to call for government intervention.
We think the next government should implement legislation to protect cash access for as long as it is needed.