British Prime Minister Boris Johnson has appealed to Conservative MPs to support legislation that could breach international law in overriding parts of his Brexit deal.
Mr Johnson hosted a conference call yesterday evening to win backing for the bill that caused Brussels to threaten legal action.
Mr Johnson told around 250 MPs that the clauses in the UK Internal Market Bill are "necessary to stop a foreign power from breaking up our country".
But during the call in which there were connection issues and no questions taken by Mr Johnson, further fall-out emerged from the EU.
Leaders in the European Parliament said they would "under no circumstances ratify" any trade deal reached if "UK authorities breach or threaten to breach" the Withdrawal Agreement.
Mr Johnson appeared not to have ended the disquiet within his party during the call, with senior backbencher Bob Neill saying he was not reassured by the speech.
Mr Neill, who is tabling an amendment to the bill which he says would impose a "parliamentary lock" on any changes to the Withdrawal Agreement, said it contains "objectionable" elements.
The European Commission has given the UK until the end of the month to drop legislation enabling ministers to override provisions in the Withdrawal Agreement relating to Northern Ireland.
Following a stormy meeting in London on Thursday, the commission warned the UK was putting trade talks at risk and said it would "not be shy" of taking legal action.
European Affairs Minister Thomas Byrne said that, far from protecting the Good Friday Agreement, the UK's actions posed a "serious risk" to the peace process.
"It's a totally unacceptable way to do business.
"This was a unilateral provocative act," he told BBC Radio 4's Today programme.