MEPs voted in en masse to add more nations and territories to the list of non-cooperative jurisdictions.
The resolution passed earlier this with votes totalling 587 to 50 and included measures calling for the automatic inclusion on the blacklist of countries which use a 0% tax regime.
This is seen as a win among transparency campaigners as the jurisdictions are widely considered havens for tax avoidance.
This week’s vote explicitly mentioned the conclusion of the Brexit deal, saying that the Brexit deal was based on “mutual values and geared towards common prosperity, which automatically excludes aggressive tax competition”.
Robert Palmer, Director of the Tax Justice UK campaign group, said: “Post-Brexit the UK tax havens have lost their protector within the corridors of Brussels. I’d expect to see the EU to ramp up pressure on places like Jersey to clean up their act. The UK itself has been warned that if the government tries a Singapore-on-Thames approach, with a bonfire of regulations and taxes, then the EU will act swiftly.”