Here is the information for how to claim double taxation relief on foreign income :-
5. If you're taxed twice
You may be taxed on your foreign income by the UK and by the country where your income is from.
You can usually claim tax relief to get some or all of this tax back. How you claim depends on whether your foreign income has already been taxed.
There’s a different way to claim relief if you’re a non-resident with UK income.
If you’ve already paid tax on your foreign income
You can usually claim Foreign Tax Credit Relief when you report your overseas income in your tax return.
How much relief you get depends on the UK’s ‘double-taxation agreement’ with the country your income’s from.
You usually still get relief even if there isn’t an agreement, unless the foreign tax doesn’t correspond to UK Income Tax or Capital Gains Tax.
Contact HM Revenue and Customs (HMRC) or a get professional tax help if you’re not sure, or need help with double-taxation relief.
What you’ll get back
You may not get back the full amount of foreign tax you paid. You get back less if either:
HMRC has guidance on how Foreign Tax Credit Relief is calculated, including the special rules for interest and dividends in ‘Foreign notes’.
You can’t claim this relief if the UK’s double-taxation agreementrequires you to claim tax back from the country your income was from.
If you haven’t paid tax on the foreign income
You have to apply for tax relief in the country your income’s from if:
- the income is exempt from foreign tax but is taxed in the UK, eg most pensions
- required by that country’s double-taxation agreement
Ask the foreign tax authority for a form, or apply by letter if they don’t have one.
You’ll then need to prove you’re eligible for tax relief by either:
Here is the link for the tax treaty between Greece and UK:-
Please let me know whether this information helps you or not and feel free to ask any query if you face one, thanks.