Do I need to pay tax in UK if I cash out the withheld earning amount that I earned in country A

Country A - country in SE Asia with no any particular treaty with UK regarding taxes. # background: I am in country a and have some earnings in Upwork (a freelancing platform). The Upwork account has been credited by the client but I have not withdrawn the amount. Now I am moving to UK in skilled worker visa and would like to withdraw the previously earned amount there in UK. # question 1 If I withdraw my earnings now in UK from Upwork, do I need to pay tax to UK? Or country A? Technically I earned while in country A so should be paid in country A. But since I am withdrawing in UK, that's the confusion. # question 2 What would be the scenario if I have the money in say paypal, wise in country A and withdraw it in UK bank when I arrive? I guess there is no tax on it not as that is not earning. # question 3 It takes 2 weeks for Upwork to credit account for existing work. Say I am in country A till Nov 14 and arrive in UK in Nov 15. Now when I move to UK, do I pay tax on earnings that is credited after Jan 15 or work done after Jan 15?

Hi Friendly_Resist824,
Please refer to guidance at Paying tax on the remittance basis (Self Assessment helpsheet HS264)
Thank you.

Dear HMRC Admin 20 I don't think I will quality for resident status as I am a new foreign individual who has never been to UK and will join on Nov end. I understand that I might miss things as I am not much familiar with taxation but in short what I am asking is as a foreign person who is travelling to UK for new job, do I need to pay tax for some amount that I earned in foreign country.

It seems I was wrong about being UK resident as I will be working about 80 working days between Nov end and April 5. So now the question would be, - do I need to pay taxes on earnings that I have before moving to uk? - do I need to pay taxes on earnings that I have before moving to uk but I move to the bank from my freelancing account?

Hi Friendly_Resist824,
Perhaps yes, perhaps no.
You would need to look at your residence status in the tax year that you arrive in the United Kingdom.
Depending on the outcome of the residence tests, you may need to declare your overseas income and claim a foreign tax credit against any foreign tax paid.
Split year treatment may apply, in which you would only declare your UK and worldwide income from the date your arrived in the UK.
Guidance on the statutory residence tests can be found here:
RDR3 Statutory Residence Test
Tax on foreign income
Thank you. 

Hi Friendly_Resist824,

The outcome here is dependant on your residency status.  You would need to confirm your residence status in the tax year that you arrive in the United Kingdom.  
Split year treatment may apply, in which you would only declare your UK and worldwide income from the date your arrived in the UK.  
Guidance on the statutory residence tests can be found at RDR3 Statutory Residence Test and Tax on foreign income.  
Split year treatment can only be claimed on a self assessment tax return.

Thank you.