The European Union should have campaigned for Remain in the June 2016 vote so it could have confronted "lies" spread by Brexiteers, a senior German politician has said, as he backed calls for a second referendum.

Elmar Brok, an MEP and close ally of Chancellor Angela Merkel, told German newspaper FAZ that a second vote could avoid a chaotic Brexit.

"If there is no exit agreement by March 29 2019 a hard Brexit will occur. So a referendum in December or January...could avert a hard Brexit," said Mr Brok, the Brexit Co-ordinator of the European People's Party.

He added, in remarks likely to infuriate Brexiteers, that the EU should have been allowed to take part in the referendum campaign in the UK to help guide the British electorate to the correct answer.

"Yes, it was a mistake that we followed the wishes of the then Prime Minister Cameron and kept us out of the campaign before the vote," he said.