FILE PHOTO: Ireland's Prime Minister (Taoiseach) Leo Varadkar arrives ahead of a European Union leaders summit after European Parliament elections to discuss who should run the EU executive for the next five years, in Brussels, Belgium May 28, 2019. John Thys/Pool via REUTERS/File Photo

DUBLIN (Reuters) - Ireland’s prime minister warned British lawmakers on Tuesday against making “a terrible political miscalculation” of thinking their rejection of the Brexit divorce deal negotiated with the European Union means they will get a better one.

Several candidates vying to replace Prime Minister Theresa May have pledged to renegotiate the withdrawal agreement May’s government struck with the EU, only for it to suffer three crushing defeats in parliament.

How to manage the land border between EU-member Ireland and British-run Northern Ireland - including an emergency “backstop” solution to prevent the return of extensive controls - has proven the most contentious element of the divorce deal.

“Like everyone in this House, I am a little concerned about political developments in London at present,” Leo Varadkar told Ireland’s parliament as a number of candidates launched their Conservative Party leadership campaigns.

“I am a little concerned that some people in London seem to think the failure of the House of Commons to ratify the agreement automatically means they will get a better agreement. That is a terrible political miscalculation.”

Ireland has insisted that the backstop remain a central part of the withdrawal deal that Varadkar described as a finely balanced compromise that was the best deal Britain could have reached, given the limited leverage of a departing country.

Outgoing European Commission President Jean-Claude Juncker also reiterated on Tuesday that the stalled divorce treaty - including the backstop - will not change with the arrival of a new prime minister in London.

“They made some miscalculations along the way,” Varadkar said of the steps Britain had taken since voters decided to leave the bloc in a referendum almost three years ago.

“Some of them thought that when push came to shove, Ireland would be abandoned and EU unity would break. They were wrong about that. I hope they are not making a further political miscalculation.”