European leaders yesterday moved to head off British Prime Minister Theresa May’s bid to rewrite the Brexit divorce deal, warning they will not budge.

Having thrown out the Brexit deal, Mrs. May negotiated with the EU, divided British lawmakers voted Tuesday to send her back to get an Irish border backstop clause removed.

Mrs. May seized on this as a chance to prevent Britain crashing out of the European Union on March 29th without an agreement on the terms of the split, vowing to return to Brussels to demand changes to the text.

But even she admits she faces a formidable challenge convincing Brussels to re-open an accord that took eighteen excruciating months to conclude, and European leaders are so far united in dismissing any such manoeuvre.