Keir Starmer is facing a major challenge to his proposed UK-wide smoking ban - from the European Union.
Seven member states have formally warned that the Tobacco and Vapes Bill currently going through Parliament is incompatible with the Brexit agreement made with Brussels because it applies in Northern Ireland.
Croatia, the Czech Republic, Greece, Italy, Portugal, Romania and Slovakia have argued that the ban will breach the Windsor Framework agreed by Rishi Sunak to avoid a hard border on the island of Ireland.
The countries, some of whom are the largest tobacco producers in the EU, argue that it would also create 'an unjustified barrier to the free movement of goods', the Times reported.
The Government believes the ban is compatible with the framework, designed to create a 'smoke-free generation' by banning tobacco products for anyone born after January 1, 2009.
It is refusing to remove Northern Ireland from the scope of the legislation. But it means it could face a legal challenge from the EU over a domestic UK law.
It is not the first warning to the government over the legislation.
Last October Northern Ireland's former legal chief warned it cannot be implemented in Northern Ireland without breaching the framework.
Seven member states have formally warned that the Tobacco and Vapes Bill currently going through Parliament is incompatible with the Brexit agreement made with Brussels because it applies in Northern Ireland.
Croatia, the Czech Republic, Greece, Italy, Portugal, Romania and Slovakia have argued that the ban will breach the Windsor Framework agreed by Rishi Sunak to avoid a hard border on the island of Ireland.
Legal advice produced by John Larkin KC for the Tobacco Manufacturers' Association, seen by the Mail, says it risks breaching a 2014 EU directive prohibiting member states - and rule-taking Northern Ireland - from making tobacco illegal.
The Windsor Framework governs post-Brexit trading arrangements and means Northern Ireland continues to follow many EU trade and customs rules to ensure no hardening of the land border with Ireland.
As well as the rolling ban on smoking, the bill would also bring in restrictions on the advertising and sale of vapes, as well as reviewing the packaging of e-cigarettes.
The legislation has passed votes in the House of Commons and is currently going through the House of Lords.
Northern Ireland Secretary Hilary Benn and other ministers have repeatedly told MPs the ban will apply to Northern Ireland.
The Department of Health said: 'The Tobacco and Vapes Bill will apply in Northern Ireland, ensuring that people in Northern Ireland will benefit from the action the government is taking to tackle the leading cause of preventable death in the UK.
'We have provided a comprehensive response to the European Commission on the detailed opinions received, setting out the reasons why our smoke-free generation policy is fully compatible with our international treaty obligations in Northern Ireland.'
