ECR group Chair Syed Kamall has said that "lessons must be learned" after it emerged that Belgium had finally agreed a deal to with Wallonia to approve a landmark EU-Canada free trade agreement, breaking a deadlock that has blocked the pact for weeks.
Prime Minister Charles Michel said the heads of the regions had drawn up an addendum to the agreement that answered their concerns over the rights of farmers and governments - an addendum that still needs the approval of Canada and other EU states.
On Thursday, Michel did not give details of the deal but tweeted, "This is an important step for the EU and Canada."
Canada called the announcement a "positive development", a cautious welcome echoed by European Council President Donald Tusk, who chairs EU leaders' summits.
But both stopped short of declaring CETA a done deal and the leader of the Flemish region, Geert Bourgeois, said the original 1598-page text of the trade deal stood.
"This is a clarification, the actual treaty does not change," he said.
All 28 EU governments back CETA, which supporters say could increase trade by 20 per cent, but Belgium had been prevented from giving its consent because of objections led by its French-speaking Wallonia region.
A major stumbling block had been the plan to create new commercial courts to handle disputes between companies and national governments.
Wallonia had feared they would give too much leverage to multinationals. It also wanted more protection for Walloon farmers, who would face new competition from Canadian imports.
Responding to the news of the apparent breakthrough, ECR group leader Syed Kamall MEP said: "Finally, the Walloon Parliament has backed down and, in true European fashion, found a deal at one minute past midnight.
"We all need to learn the lessons from this debacle, not least that it is incumbent on all supporters of open trade to go out and make a positive case for the benefits of it."
Further reaction came from ECR group trade spokesperson Emma McClarkin, who said, "It makes you wonder why they dragged this out so long. Canadian Prime Minister Justin Trudeau could have been in Brussels signing this agreement today with fanfare. Instead he has cancelled his trip with a bad taste in his mouth.
"The credibility of the EU on global trade deals is in tatters following this debacle. CETA is one of the highest quality agreements ever negotiated, with a country that has values and standards very similar to our own.
"Other countries will now ask whether it is worth the time and effort conducting such deals with the EU. We need to show them that the EU can be a reliable trade partner."
Her colleague David Campbell-Bannerman said: "This is an excellent deal nearly lost. It is clear that a great deal more time needs to be spent listening to concerns in different member states, and in trying to overcome them.
"CETA will eliminate 99 per cent of tariffs between the EU and Canada, save EU exporters €500m a year and increase trade by 20 per cent. This agreement, and the benefits it will bring to the economies across the EU are worth fighting for. It may also be the basis of a new EU-UK trade deal so its implications are very great indeed."