In EU there are strict financial regulations about custody. Brokers are not allowed to do anything to your shares without your instruction. So, for example, if

In EU there are strict financial regulations about custody. Brokers are not allowed to do anything to your shares without your instruction. So, for example, if the broker goes bankrupt, the custody account with your shares is still there for you. I assume it is still the same in the UK post-brexit, but I have not looked it up.