Alternative phone number options in the UK?

Google Voice isn't available in the UK. What other options are there to have another number?

Another phone/sim? I find this extra, wondered if there were other options people had tried.

Edit - iPhone allows you to have multiple e-sims or an e-sim + physical sim in one phone. Option to have two numbers. 

One personal, and one for men/other things that if it becomes problematic, you can just quickly change (pay as you go sim).