Andrews has organised a letter, signed by 31 members and sent to the European Commission, which outlines a series of demands designed to salvage the Withdrawal Agreement.
His move comes with some predicting a collapse of the trade talks which resumed on Monday in Brussels between the EU and UK.
Over the weekend Council President Charles Michel warned that the UK's reputation was at risk and Michel Barnier and David Frost were involved in a spat after sending tweets about the latest Brexit row.
A key part of the Withdrawal Agreement - which is now an international treaty - was the Northern Ireland Protocol, designed to prevent a hard border returning to the island of Ireland.
The Internal Market Bill proposed by the UK government would override that part of the agreement when it came to goods. British MPs are due to vote on the Bill later on Monday.
Just ahead of the resumption of the talks, Andrews told this website, “Many of my colleagues in the European Parliament and I are extremely concerned by recent developments in the UK and the implications these could have for the UK’s implementation of the WD and the Protocol on Ireland/Northern Ireland.”
“I have received cross-party support for this letter from 31 of my colleagues including Fine Gael, the Green Party, Sinn Féin, Independent MEP Luke Ming Flanagan and my party colleague Billy Kelleher, as well as support from other colleagues across the EU” Barry Andrews MEP
He adds, “To this end, I have gathered the co-signatures of fellow MEPs in addressing a letter to the Commission Vice-President Maroš Šefčovič, Co-Chair of the EU-UK Joint Committee, calling for clarification on how the Commission would respond to any breach of the Withdrawal Agreement and to seek assurances that any deal on the future relationship will be conditional on the full implementation of the Withdrawal Agreement, including the Protocol on Ireland/Northern Ireland.”
Andrews, a member of Parliament’s International Trade Committee, said, “I have received cross-party support for this letter from 31 of my colleagues including Fine Gael, the Green Party, Sinn Féin, Independent MEP Luke Ming Flanagan and my party colleague Billy Kelleher, as well as support from other colleagues across the EU.”
“The EU must make clear that it will not tolerate any breach of the Withdrawal Agreement or the Protocol on Ireland/Northern Ireland. The UK must urgently explain its position as unilateral changes to the Withdrawal Agreement would not only constitute a breach of international law, but would severely undermine efforts to preserve the all-island economy and avoid a hard border in Ireland. They also risk putting an end to any prospect of a deal on the future relationship,” said Andrews, an RE member.
On Sunday, the British Justice Secretary Robert Buckland told the BBC he hoped powers being sought by ministers would never be needed, and that he would resign if the UK ended up breaking international law “in a way I find unacceptable.”
UK MP Sir Desmond Swayne said he would be supporting the bill, praising the government for preparing in case no trade deal is agreed by the end of the year.
He told BBC News, “If the government didn't take precautions against that possibility, it would be utterly negligent. It is right to harm itself with the powers just in case.”
“I have gathered the co-signatures of fellow MEPs in addressing a letter to the Commission Vice-President Maroš Šefčovič, Co-Chair of the EU-UK Joint Committee, calling for clarification on how the Commission would respond to any breach of the Withdrawal Agreement” Barry Andrews MEP
David Cameron has become the fifth former prime minister to criticise the Internal Market Bill, which attempts to override the Brexit Withdrawal Agreement. The Bill will come before MPs on Monday evening, with the government calling it an “insurance policy.”
Cameron said he had “misgivings” over it and breaking an international treaty should be the “final resort.” Former Tory Prime Ministers Theresa May and Sir John Major, and Labour's Tony Blair and Gordon Brown have condemned the plan.
The UK left the EU on 31 January, having negotiated and signed the Withdrawal Agreement with the bloc.
The two sides are now in the closing weeks of negotiations for a post-Brexit trade deal before the transition period ends on 31 December - with informal talks taking place in Brussels this week.
On Friday, political group leaders in the European Parliament and the UK Coordinating Committee met with Chief EU Negotiator Michel Barnier and Šefčovič, who was fresh back from emergency talks with the UK’s Michael Gove.
A statement said, “The Internal Market Bill clearly represents a serious and unacceptable breach of international law. It violates the Withdrawal Agreement that was signed and ratified by the current UK Government and Parliament less than a year ago.”
“The Internal Market Bill gravely damages the trust and credibility that the European Parliament has already said is ‘an essential element of any negotiation’, thus putting at risk the ongoing negotiations on the future relationship.”
Parliament, it adds, supports the EU in asking the UK government to withdraw the measures from the bill immediately “by the end of September, at the very latest.”
On Monday, at a press briefing, a Commission spokesman was asked about the latest assertions, made over the weekend, by both the EU and UK.
But he said, “We have said and written on all that is necessary on this issue for now. But I repeat that the Withdrawal Agreement is the framework for our relationship with the UK – there are no ifs or buts.”
“We have played a straight bat on this and the rest is all internal debate in the UK and we are not getting involved in that.”