Scotland has lost more than a third of its bank and building society branches in just eight years, new analysis from Which? Money reveals.
Some 610 branches have closed down between 2010 and 2018, while Scotland has lost more than 200 ATMs in the past year.
The Scottish Affairs Committee is meeting in Westminster this week to probe the issue of dwindling cash access north of the border.
MPs on the committee have been highly critical of banks following a spate of Scottish branch closures, stating in a 2017 report that banks do not 'fully appreciate the damage these closures will do to the communities and businesses.u201d
Which? has submitted several items of research to the committee ahead of its latest inquiry.
The number of banks and building society branches in Scotland plummeted from 1,625 to 1,015 between 2010 and 2018, according to figures compiled by the Office for National Statistics, which we have analysed.
We've tracked 399 closures north of the border in a little over three years. This includes existing branches that have been scheduled to close this year.
RBS has closed the most branches (158), followed by Bank of Scotland (86), Clydesdale (59), Santander (38) and TSB (35).
These figures do not account for any branches that may have been opened during the period. Nor do they reflect the proportion of branches which have closed - RBS and Bank of Scotland both have a very large presence in Scotland.
Scotland lost 204 free-to-use cash machines last year - amounting to more than 4% of the entire network.
Which? is calling on the UK Government to give a single regulator a duty to protect access to cash and ensure no-one is left behind by these rapid changes to the payments landscape.
We believe intervention is badly-needed in rural areas, where people struggle to access cash and basic banking services while also suffering from poor broadband and limited connectivity.
However, cash access is equally necessary in urban areas, where it provides a back-up when card and cashless payment systems collapse.
Gareth Shaw, Head of Money at Which?, said: 'Communities across Scotland could be left struggling to access the cash that millions of people still rely on in their daily lives through rapid closures of bank branches and cashpoints.'
The data did not reveal how long each IT outage lasted for how many customers were affected.
Gareth Shaw said: 'Cash is a vital backup when digital systems do fail - so the UK Government must appoint a regulator to oversee these changes and ensure no-one is shut out from paying for local goods and services.'
Gem Turner, from Yorkshire, says she needs cash to do the 'everyday things a 25-year-old wants to do'.
Gem has brittle bones and uses a powered wheelchair in her work and social life.
She told us: 'Accessing cash can be really difficult for disabled people. Getting to the cash machine is like a military operation.