You can look at banks' financial reports. Santander's (https://www.santander.co.uk/assets/s3fs-public/documents/Santander%20UK%20plc%202024%20Annual%20Report.pdf) says £60 billion in "Cash, repos, other financial assets and other assets non-interest earning" and £176 billion in customer deposits.
You can look at banks' financial reports. Santander's (https://www.santander.co.uk/assets/s3fs-public/documents/Santander%20UK%20plc%202024%20Annual%20Report.pdf) says £60 billion in "Cash, repos, other financial assets and other assets non-interest earning" and £176 billion in customer deposits.