NATO Salary

Hi, I understand that NATO employees are exempt from tax on their salaries under the Ottawa Agreement (Article 19). If an individual is based in Belgium (but who is resident and ordinarily resident in the UK), would this tax free status of the NATO employment extend to it not being declarable for tax purposes in the UK? Thank you

Hi
An individual who is in the direct employment of one of the NATO Headquarters is entitled to exemption from Income Tax on his emoluments provided they
hold a permanent administrative assignment
are not a member of the locally engaged staff and
are remunerated in accordance with NATO established salary scales.
The exemption applies irrespective of their citizenship.