The European Union’s remaining 27 leaders will declare the EU to be “undivided and indivisible” at an anniversary summit today, despite the looming reality of Brexit and weeks of bitter disagreement over the text of the Rome Declaration setting out the future of the bloc.

The EU leaders will put on a brave face when they gather for a "unity summit" on top of Rome’s Capitoline Hill and renew the EU’s marriage vows in a ceremony to mark 60 years since the signing of their founding document, the 1957 Treaty of Rome.

Looming over the summit will be Theresa May’s decision to trigger Article 50 next week and begin formal talks to secede from the Union – a reality reflected in the fact that Mrs May will be absent from Saturday’s line-up of leaders.

Preparations for celebration have been marred by deep divisions among EU members, with Poland and Greece both threatening to refuse to sign a formal declaration unless given concessions on issues, including immigration and austerity.