Michel Barnier has said Britain could regain its special terms if it rejoined the EU and claimed it was becoming clearer every day to the British people that they would be stronger in Europe.
In an interview before the 10th anniversary of the Brexit referendum next week, the EU’s former chief Brexit negotiator said he could not see any obstacle to the UK keeping the pound and remaining outside the passport-free Schengen travel area should the country rejoin.
The comments cast serious doubt on suggestions from some authoritative voices, including Poland’s foreign minister, that the UK could be forced to accept more difficult terms on re-entering the bloc.
They will be seen as a boost to those who are campaigning for the UK to rejoin the EU, with polling showing that support for rejoining is stronger when the old terms are on the table.
Under the EU treaties, all member states are expected to join the euro, apart from Denmark, which has a permanent opt-out.
New member states are also legally obliged to join the Schengen passport-free area once they meet the necessary technical, legal and security requirements.
Barnier, who remains an influential voice in Brussels and was prime minister of France in 2024, said he believed the UK would be able to regain exemptions given the precedents already set.
He said: “I am speaking about Schengen, I am speaking about the single currency: there are other member states who are not in them. It is perfectly possible to have opt-outs in these fields.”
Five of the 13 countries that have joined the EU since 2004 are yet to join the single currency. The treaties do not specify a particular timetable for joining the euro area.
Ireland is the only EU member state with an official opt-out from the Schengen passport-free travel area.
Barnier, who continued as a Brexit adviser to the European Commission until his return to French politics, said he did not want to comment on whether the UK could also keep the rebate secured by Margaret Thatcher, which reduced the UK’s financial contributions to the bloc’s budget.
He said: “The DNA of the EU is solidarity that the more developed country helps the other … We will see if the UK decides to ask to join the EU. It will be a choice and it will be open to negotiation. I will be ready at that time for free advice.”
Barnier will be in London on Tuesday for a UK in a Changing Europe conference marking the decade since the Brexit vote. He spoke to the Guardian before this week’s announcement that the next round of UK-EU “reset” talks will take place in Brussels on 22 July after several delays.