Theresa May's attempt to break the deadlock in Brexit negotiations will fail unless she guarantees the rights of millions of European Union (EU) citizens living in Britain, demonstrators have warned.

A group of about 30 gathered in the piazza in front of the Santa Maria Novella basilica in Florence where the Prime Minister is due to deliver a key speech on Brexit designed to push faltering talks forward.

Former Labour MP Roger Casale, who organised the demo for the New Europeans campaign group, called on Mrs May and the EU to unilaterally make guarantees for 3.4 million Europeans in the UK and the one million or so British expats on the continent.

Among the protesters were Italians and Florentines who live in the UK and Britons who live in Italy.