Taxation for draw down on a US based IRA?

I am living in the US and planning to move to the UK and be resident for tax in the UK in 2025. I have a US based 401K that I am going to rollover to a US based IRA so that I can have access to drawn down from it when in the UK as part of my pension (or before). Therefore I will be bringing money back into the UK when I need it. How will this be taxed in the UK, is it purely taxed as income?

Hi,
HMRC cannot comment on future events as legislation and/or plans may change.
Thank you.