Thousands report Lloyds, Halifax and TSB banking apps not working

Lloyds, Halifax, Bank of Scotland and TSB are all subsidiaries of the same organization, so will likely share infrastructure. But First Direct (which I believe are part of HSBC), Barclays, and Nationwide are not, and I believe are all unrelated to one another.

According to the Register, it's Lloyds Bank, Halifax, TSB, Nationwide, First Direct, Bank of Scotland, and Barclays.

Interestingly, all the banks seem to have the exact same notice on their websites about this. (See https://www.theregister.com/2025/02/28/payday_from_hell_as_s... )

None of the reporting on this seems to report a cause for what might be behind this. A concerted DDoS campaign? Failure of some shared common facility? Nation-state-level hacking?