Theresa May believes there is an attempt to unpick the deal on the Irish border STEFAN ROUSSEAU/PA

The European Union has demanded that Britain effectively hand over sovereignty of Northern Ireland to Brussels if it cannot find a solution to the Irish border question.

In an uncompromising legal text published today, the Commission also calls on the UK to make Europe’s highest court the ultimate arbiter of any Brexit disputes.

The EU has also rejected British proposals that cover the transition period. The document states that EU citizens arriving after March 2019 must have identical rights to those already living in the UK.

It also gives the European Commission powers to suspend Britain’s access to the single market unilaterally if Brussels believes the UK has broken the terms of the agreement.

All the demands will be rejected by the government, potentially jeopardising…