Currency exchange and capital gain

Dear HMRC Administrator, I have been granted entry clearance to the UK under the BN(O) Visa scheme. I am planning to arrive UK a couple of months from now. Currently, I have money holdings in HKD, USD, EURO and GBP. I will convert some of my holdings into GBP before and after my arrival in the UK. The aforementioned foreign exchange conversion is not for trading purposes. There would certainly be price fluctuation in the currency market. I wonder if I need to keep track of all currency exchange transactions and report the gain/loss for taxation purposes for relevant financial years? Thank you for your advice. Regards, Jones.

Hi Je77 Jones,
If the capital brought into the UK, arises in a tax year you are not resident in the UK, then there are no tax implications.
If you are resident in the UK in the tax year it arises, then there could be a tax implication.
You would need to review the guidance on statutory residence and take the test and if necessary, confirm if split year treatment applies to your circumstances.
RDR3 Statutory Residence Test
Thank you. 

Dear HMRC Admin 25, Thank you for your reply. May be I should rephrase my question with the following example: Before 6/4/2024, I had never lived in UK. I had cash holding of HKD 1 M, USD 0.2 M, GBP 0.3 M and other currencies for travelling. I will arrived in UK on 16/7/2024. Between 6/4/2024 and 15/7/2024, I convert some HKD into USD and GBP. After I arrive UK on 16/7/2024, I convert also some more HKD to GBP, and some USD to GBP. I will have cash holding of less than 1 M HKD, less than 0.2 M USD and more than 0.3 M GBP. The aim is to convert other currencies into GBP (as the base currency) for UK living. I stay in UK from 16/7/2024 for the rest of the financial year (more than 183 days) in a permanent location. It appears that I am a resident in the UK for the tax year. As mentioned above, I am planning to convert other currencies in GBP for UK living. Since there are fluctuations in the currencies market, to ascertain whether there is any "capital gain" or "capital loss" arising from currencies conversion, will I need to take a snapshot of the holding position at 6/4/2024 (HKD 1M, USD 0.2M and GBP 0.3 M) converted them into GBP (using UK's official rate) and compare the equivalent GBP cash holding position at 5/4/2025 to work out the "gain" or "loss" for considering tax implication? Thank you for your advice. Jones. I have been granted entry clearance to the UK under the BN(O) Visa scheme. I am planning to arrive UK a couple of months from now. Currently, I have money holdings in HKD, USD, EURO and GBP. I will convert some of my holdings into GBP before and after my arrival in the UK. The aforementioned foreign exchange conversion is not for trading purposes.

Hi Je77 Jones,
We are unable to comment on scenarios.
You would need to review the guidance on statutory residence and take the tests here:
RDR3 here:
RDR3 Statutory Residence Test
If you are treated as tax resident for the full tax year, you will need to check if split year treatment applies.
If it does, then there would be no UK capital gains implications on currency transactions before you arrive in the UK.
Please also have a look at the guidance on foreign currency here:
CG78300 - Foreign currency: introduction
For a more indepth answer to a detailed question of this nature, you would need to contact our Self Assesment helpline or seek professional advice.
Self Assessment: general enquiries
Thank you.