WobblyBus

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?

I have a similar case here. If the shares are then sold what would the tax liability be in the UK and also USA? Also due to the tax differences would I be better off selling all my shares whilst I am still in the US employed or after I move back to the UK in 6 months time. I currently pay at a tax rate of around 25% in the USA.