The European Commission's budget chief has risked further inflaming tensions with Britain's Brexit negotiators by declaring that the UK "must continue to make payments to the EU" until 2023.

Gunther Oettinger, the budget commissioner, who is not part of Michel Barnier's negotiating team, said "the European Union expects the British to hold commitments". He went on to suggest that the country should continue making contributions to Brussels for four years after its departure in 2019.

On Saturday John Redwood, the former trade secretary, described the idea by the prominent German politician as "completely idiotic", saying that there was "no way" the demand would be met.