Calculating tax on part surrender of onshore non-qualifying life assurance policy

I am considering making a withdrawal from my onshore non-qualifying life assurance policy. I realise that the amount withdrawn will be a chargeable gain as I have a used up all my 5% allowance on previous withdrawals. Please advise where I might find information on how to calculate the tax liability for this event. I am aware of tax calculations for full surrender but am concerned that there might a different method for part surrender. Many thanks

Hi,
Please refer to guidance at HS320 Gains on UK life insurance policies (2024)
Thank you.

Thank you for your reply. HS320 tells me how to calculate a gain but does not show how to work out the tax liability. I have already worked out the amount of gain and now I need to know how much tax I would have to pay on it. IPTM3850 gives worked examples of tax liabilities on full surrender of policies so should I assume that these calculations are the same for part surrender of policies? I am only querying this because I have read somewhere in the manuals (I've forgotten where) that tax calculations on part surrenders are a little more complicated. I may be entirely mistaken in this and if so I apologise in advance. Thank you

Hi,
You can see guidance here:
IPTM3540 - Calculating gains: part surrenders and part assignments: ‘periodic calculations’ and ‘excess events’
The calculated gain is added to your income and your liability is calculated.
Thank you.