Hi,
Please have a look at articles 18 and 19 of the UK/Turkey double tax agreement below:
UK/TURKEY DOUBLE TAXATION AGREEMENT
If you have relocated to Turkey and you have commenced reciept of your private pensions, you would complete the form below and declare your private pensions, including state pension:
Double Taxation: Treaty Relief (Form DT-Individual)
Please send the completed form to the Turkish tax authorities for validation. They will return the validated form to you, so that you can then send the validate form to:
HM Revenue and Customs,
Pay As You Earn and Self Assessment,
BX9 1AS,
United Kingdom
Thank you.