The Northern Ireland Affairs Committee has expressed its disappointment after Brexit Secretary David Davis declined to appear before it.
The NI Affairs Committee had wanted to discuss the lack of a viable solution to the Irish border with the Mr Davis.
The committee said that due to the lack of an obvious technical solution from the evidence received they did not believe that a frictionless post-Brexit border would be possible and invited Mr Davis to appear before them to update them on the issue.
Mr Davis declined, saying he had already given evidence relating to Northern Ireland before the Exiting the European Union Committee and the Lords EU Committee.
He suggested that the committee invite Robin Walker MP (Department for Exiting the European Union) and Shailesh Vara MP (Northern Ireland Office) to speak in his place.
Mr Walker and Mr Vara's predecessor, Chloe Smith MP, had already appeared before the NI Affairs Committee in November 2017.
The committee said they specifically requested Mr Davis appear due to his role as lead negotiator for the United Kingdom and given the central importance of a Northern Ireland border solution to the Brexit process.
His opposite number, the EU’s Michel Barnier, has already given oral evidence to the committee
Committee chairman Dr Andrew Murrison MP said they felt asking Mr Davis to give evidence was a "reasonable" request.
“My committee is most disappointed that David Davis has turned down our invitation to give evidence on what all agree is an absolutely pivotal element of the Brexit process. Michel Barnier has given us oral evidence as EU negotiator and the committee felt it would be reasonable to ask his UK counterpart Mr Davis to do the same," Dr Murrison said.
“This is more urgent now as a technical solution to the border is one of two options cited by ministers. Given the committee’s caution over the prospects for a technical solution in it’s original report on the Irish land border post Brexit, we wanted to give the minister an opportunity to say what progress had been made.
"We would then be happy to update our report if warranted by evidence received. Otherwise, clearly, we cannot and the opinion expressed in the original report will have to stand.”
A Department for Exiting the European Union spokesperson said they were committed to ensuring a frictionless border in Ireland.
"The Secretary of State for Exiting the European Union takes his parliamentary commitments extremely seriously. He has provided evidence to the Exiting the EU Committee six times, and to the Lords EU Committee five times - and has answered numerous questions in relation to the negotiations and Northern Ireland at both."
"Our policy is clear - we are committed to ensuring there is no hard border between Northern Ireland and Ireland and to ensuring the same unfettered access for Northern Ireland's businesses to the whole of the UK's internal market. We have set out our preferred customs models to enable trade to remain as frictionless as possible.
"The UK remains committed to all the scenarios outlined in the Joint Report, and following March European Council, the UK and EU negotiating teams are now engaged in ongoing discussions on these issues."