The letter orders governments to “hold accountable EU operators that have been actively undermining EU sanctions, wherever they are active,” and deter companies from exploiting sanctions loopholes by publishing the “more illustrative” cases and their penalties.

McGuinness also tells member countries to contact companies involved in the manufacturing of sanctioned goods to push them for more due diligence of their supply chains to comply with EU sanctions rules.

National authorities should share more information on non-EU companies and individuals that may be involved in exploiting sanctions loopholes, and should be “exercise particular vigilance” about sanctions exemptions that could make the problem worse, the letter says.

Huge problems

The idea of creating a European authority for sanctions enforcement has proved popular in the past, with around 10 countries, including Germany, France, Italy and Spain, backing a Dutch-led push for such a body last year.

France lobbied last year for the powers of the European Public Prosecutor’s Office to be extended to cover sanctions loopholes.

A senior EU diplomat, also granted anonymity to speak freely, said there were “huge problems” with the sanctions rollout, including “uneven” takeup from one country to another.