The Government has failed to provide any evidence that it will be able to avoid introducing a hard border between the UK and Ireland after Brexit, an influential House of Commons committee has said.

The Exiting the EU Committee said it appeared inevitable that border checks will have to be introduced if Britain leaves the single market and customs union.

Government ministers have insisted that there will not be a hard border between the UK and Ireland after Brexit, but have also committed to withdrawing the UK from the single market – positions that are difficult to reconcile, according to the committee.

The option of allowing Northern Ireland to remain in the trading bloc when the rest of the UK leaves has been mooted but any such proposal is likely to be strongly opposed by the DUP, whose votes the Conservatives rely on in Parliament.

The Brexit committee said Government suggestions that technology could be used to create a “light touch” border were “untested and to some extent speculative”.

Hilary Benn MP, who chairs the committee, said: “Our report concludes that we cannot at present see how leaving the customs union and the single market can be reconciled with there being no border or infrastructure.

“Even by their own admission, the Government’s proposals are untested and speculative, so it has yet to set out how no border can in practice be maintained with the UK outside the single market and the customs union.”

The issue of how the Irish border will be managed after Brexit has proved to be a major sticking point during Brexit negotiations.

EU leaders will meet on 14 and 15 December to determine whether talks should progress to the next phase, which would focus on the prospect of a future trade deal.

Leo Varadkar, the Irish Taoiseach, has threatened to stop talks progressing unless the UK Government clarifies its plans for managing the border after Brexit.

Ireland wants a written guarantee that there will not be a return to a hard border, but UK ministers have so far declined to clarify how this would be achieved.

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

The Brexit committee called on the Government to publish a report on the Brexit implementation period in order to remove uncertainty for businesses. This should cover a range of issues, MPs said, including the UK’s participation in the single market and customs union, membership of EU agencies and what will happen to freedom of movement.

Mr Benn said: “Businesses need certainty and reassurance to stop firms triggering contingency plans which could see activities and jobs move abroad. Ministers assured us that detailed arrangements for the implementation period could be published by March 2018. This deadline must be achieved.”

“The Government should also set out its vision for the UK’s future trade relationship with the EU. If phase two of the talks do start next month, then ministers need to move beyond words like ‘bespoke’ and ‘special’ and actually explain what it is they are seeking.”

The committee also said it would “not be acceptable” to give MPs a vote on a Brexit deal once the UK has already left the EU.

David Davis suggested last month that such a vote could take place after Brexit but was swiftly contradicted by Theresa May, who said MPs would be given a say before Britain leaves the EU in March 2019.