A simple bill of attainder would do it, but she'd have recourse to the ECHR to appeal it, which would in practice bind the UK. If we thought she wasn't going to be chill with it, we'd first need to withdraw from the ECHR. As it happens, withdrawing from the the ECHR is a prime Farage objective.

Human rights only apply to those what are willing to defend them.

What’s Europe going to do, send in a deal team to extract Adele?