The UK could be sued by European Union judges if Labour implements a controversial smoking ban. The new rule would prevent anyone born after January 1, 2009 from ever being able to buy cigarettes as the legal smoking age will rise one year, every year.

However, the Tobacco and Vapes Bill may risk breaking EU law if it is applied to Northern Ireland as it is subject to the jurisdiction of the European Court of Justice and a plethora of Single Market Rules due to the Windsor Framework.

This was implemented to keep peace with Ireland post-Brexit. However, if prime minister Sir Keir Starmer applies the ban to Northern Ireland, Brussels could fine Britain or introduce tariffs, Greece, Slovakia and Romania have told the European Commission. On the other hand, not implementing the ban in Northern Ireland would create a “smoking border”, which would have to be added to the Windsor Framework’s Irish Sea customs border with Britain.

A Government spokesperson said: “We believe the Bill is consistent with the Windsor Framework, and it will apply UK-wide.”

They added: “The bill has not been blocked, and its passage has not been delayed.”

Greece, Romania and Slovakia have submitted opinions to Brussels arguing that the ban would boost the black market for cigarettes, as well as breaking EU rules on the free movement of goods.

A European Commission spokesman told The Telegraph: “It is now for the UK in respect of Northern Ireland to report on the action it proposes to take in view of the detailed opinions. The Commission will comment on that reaction.”

They added: “In the meantime, the Commission has no comments to offer on the substance of the matters subject to this procedure.”

The smoking bill is currently in the House of Lords after passing the House of Commons. In order to take effect in Northern Ireland, Stormont must also approve of the ban due to health being a devolved power in the UK.

If Britain and the EU do not reach an agreement on whether the ban can be implemented in Northern Ireland, Brussels may launch legal action if London defies a ruling from EU judges.

The Commission may also opt for tariffs on the UK, or even the cancellation of the trade deal for breaking Brexit obligations.