ST JULIAN’S, Malta (Reuters) - Pro-European allies of German Chancellor Angela Merkel on Thursday set out a firm line on Britain’s exit negotiations, including an exit bill for London among the main priorities of the EU’s overall stance.

With control of the main EU institutions in Brussels and counting EU negotiator Michel Barnier among their ranks, the center-right European People’s Party (EPP) will be one of the most important pressure groups behind the scenes of the talks.

At a two-day congress dominated by Britain’s formal decision to quit the bloc on Wednesday, Europe’s most powerful political family said it will seek to ensure the rights of EU citizens in Britain continue, that Northern Ireland avoids a hard border with Ireland and that London settles its accounts on leaving.

“The exit bill must be paid in full by the United Kingdom,” said Frenchman Joseph Daul, leader of the EPP that is broadly made up of center-right Christian Democrats.

The party “will not allow the cherry-picking we saw over the past few decades,” chairman Manfred Weber said, adamant that Britain cannot shape the new future relationship in the way London did as an EU member, opting in and out of certain areas.

A possible bill of 60 billion euros ($64 billion) has been mentioned in Brussels since last year, but officials stress it is only a very rough estimate and needs to be discussed in two exit negotiations that are expected to start in mid-May.

“NOW WE ARE THREE”

To the music of the 1970s hit “We Are Family” at a luxury hotel in Malta, the EPP pledged not to allow Britain to exploit divisions between center-right governments during the talks.

Although a now familiar promise by all European Union leaders, it may hold more weight because of the divisions among European socialists, particularly in France, traditionally a twin engine of the European Union along with Germany.

German Chancellor Angela Merkel takes part in a European People Party summit in Malta. REUTERS/Darrin Zammit Lupi

In tatters, France’s ruling Socialist Party is almost certain to lose power in this year’s elections, while the left has lost ground in southern Europe and is not assured of unseating Merkel in Germany’s elections later in September.

“We are united to respond to whatever letters come from London,” said EPP secretary general Antonio Lopez-Isturiz. “I challenge the Socialists to have such a gathering,” he said to an audience of hundreds of delegates. “I challenge them to organize a football team.”

Former British premier David Cameron took the Conservatives out of the EPP in 2009 to appease euroskeptics in his party but at the cost of lost influence in the political group.

Croatia’s Prime Minister Andrej Plenkovic was scathing about Cameron, blaming him for allowing internal divisions within the Conservatives to lead to Brexit.

“Never allow an intra-party question to become a national, a European or a global question,” he told the congress.

EPP leaders including Irish Prime Minister Enda Kenny relished in the EPP’s upswing that saw it win the presidency of the European Parliament and regain the presidency of the European Council, which chairs EU summits, this year.

He noted negotiator Barnier was a member of the center-right grouping and called for EPP support to avoid problems that its withdrawal from the EU will create on the Irish border, as well to include a 1998 Irish peace deal in a final Brexit accord.

“Now we are three!” the new president of the EU legislature Antonio Tajani declared to hundreds of members of the party faithful, referring to the EPP control of the European Parliament, the Council and the Commission.

Merkel called that “a major success” but told the party it now had the responsibility not to abuse its position and uphold values of fairness and solidarity, although she did not directly mention the Brexit negotiations.

“We have to find answers now ... We have problems to solve at the European level,” Merkel said, citing migration and combating Islamic militants, areas that will involve Britain.