Early evidence from Europe, where they already have negative rates, shows that so far it’s only the wealthiest who are paying banks “reverse interest” on cash balances of hundreds of thousands of euros or Swiss francs. I cannot see banks in the UK passing on charges to everyday savers. For one, it would cause uproar and could create liquidity issues if people swapped banking over-the-counter for under-the-mattress. And with studies showing millions of Britons have no savings at all, charging for deposits would do nothing for financial resilience.

https://www.ft.com/content/0c282e4e-5ba4-42a8-969c-d8ba48919566