Theresa May was forced to intervene on Tuesday after two of her most important Brexit Cabinet ministers appeared to fall out over the terms of Britain’s exit from the European Union.

The row is deeply embarrassing for the Prime Minister, coming eight days after the formal start of Brexit talks with the European Commission.

The dispute centred on whether Britain will leave both the single market or customs union, or remain in a lengthy transition period to allow companies to adapt.

David Davis, the Brexit Secretary, told a conference in London that the UK will be out of the EU customs union and single market by March 2019.

He said he expected the UK to have left the arrangements within the two-year timetable set out under the Article 50 process.