A senior Tory MP hit out at “shroud-waving” EU negotiators as he claimed a hard Irish border would not materialise as no-one wanted to build it.

Julian Lewis, chairman of the Commons Defence Select Committee, pressed Prime Minister Theresa May to ask who would construct such a border, the next time it is raised as a prospect by Brussels.

Agreement over the Irish border has proved to be a difficult issue to resolve during Brexit talks, although a Belfast academic has insisted a hard border is unavoidable in the case of no-deal.

Brexit
Anti-Brexit billboards on the northern side of the border between Newry in Northern Ireland and Dundalk in the Republic (Niall Carson/PA)

Speaking at Prime Minister’s Questions, Mr Lewis said: “The next time shroud-waving EU negotiators claim a hard border is necessary on the island of Ireland, will she kindly ask them who would actually construct it?

“The Irish certainly won’t, the British certainly won’t, so unless the EU army plans to march in and build it, it surely can never happen.”

Mrs May replied: “We’re all working to ensure there will be no hard border between Northern Ireland and Ireland, that is the clear commitment of the United Kingdom Government, as agreed by the European Union when we signed the December joint report.”

However, Queen’s University Belfast academic Katy Hayward said the arguments of Brexiteers like Mr Lewis had “no validity”.

Speaking at a Brexit update from the independent thinktank UK in a Changing Europe, Dr Hayward said arguing a hard border would be unnecessary in a no-deal scenario “ignored the realities of world trade today”.

She said: “The truth is if the UK leaves the EU, systems that have kept that border open, then of course there will be consequences, and there will be a hard border.

“A lot of the points made by Brexiteers underestimate the extent at which the EU and EU integration has facilitated cross-border co-operation and all the mechanisms that go along with that.

“Those are the kinds of laws, policies and regulations they resent – but they have a function and that is to keep a border open and make it as frictionless as possible.”