Hi Bvb23,
HMRC is legally permitted to exchange information with overseas tax authorities to assist with compliance and to tackle tax evasion.
IEIM400000 - Automatic exchange of financial accounts information.
This guidance manual explains the principles involved in exchanging such information, together with the procedures to follow.
The Asian Development Bank's status as a 'Non-Reporting Financial Institution' is in the context of those procedures and does not provide commentary on possible exemption from UK tax for employees of that bank.
Employees of 'International Organisations' can instead refer to the International Manual, at references:
INTM860700 - Immunities and Privileges: Contents: International Organisations
For guidance on potential claims to exemption.
INTM860700 - Immunities and Privileges: Contents: International Organisations
Onwards.
Thank you.