DMBM560015 - Debt and return pursuit: foreign cases: Mutual Assistance in the Recovery of Debt (MARD) (EU States): about the agreement You should check the other guidance available on GOV.UK from HMRC as Brexit updates to those pages are being prioritised before manuals.
What is MARD? MARD (Mutual Assistance in the Recovery of Debt) is an arrangement which allows a relevant authority in another country to ask HMRC for assistance in either: obtaining information recovering a tax or duty debt where the defaulting taxpayer is living in, or has assets in, the UK. There are a number of different MARD arrangements in place, but all are reciprocal.