Under ideas for a four-tiered system devised by France and Germany, Britain might become a “associate member” of the European Union.
The report presented by Paris and Berlin includes recommendations for EU reforms as the EU seeks to expand.
It proposes four layers of integration, beginning with the “inner circle” of Eurozone and Schengen Area members, followed by a second tier of remaining EU members.
An outer third tier would consist of “associate members” who would join the single market while adhering to the bloc’s common ideals and values.
The existing European Political Community, of which the UK is already a member, would be the fourth outer layer, focused on “geopolitical convergence and political cooperation” in areas such as climate policy, security, and energy.
The report says countries such as Norway, Switzerland or “even the UK” – which left the EU in 2020 – could be in the third tier.
It says: “Associate members would not be bound to ‘ever closer union’ and further integration, nor would they participate in deeper political integration in other policy areas such as justice and home affairs or EU citizenship.
“Still, the basic requirement would be the commitment to comply with the EU’s common principles and values, including democracy and the rule of law. The core area of participation would be the single market.”
Countries that become “associate members” would be expected to pay into Brussels’ budget although fees would be less than full members with “lower benefits”.
They would also be subject to the jurisdiction of the European Court of Justice, which is based in Luxembourg.
Those in the third tier would be represented by speakers within the European Commission and Parliament, but would not be able to vote.
It comes as Labour leader Sir Keir Starmer has set out his vision for a closer partnership with Brussels if his party takes power at the next general election.