David Cameron at the Supporting Syria Conference | Getty Images Cameron ‘finally’ accepts European Parliament invite After resisting for months, the UK premier will talk to EU party leaders — who include Farage and Le Pen.

British Prime Minister David Cameron accepted a long-standing invitation to speak at the European Parliament, where he will appear on February 16, two days before EU leaders discuss his proposals for reformed U.K. membership of the EU at a summit.

European Parliament President Martin Schulz, who has been pushing for Cameron to explain his views on the Brexit debate to the assembly since September, extended the invitation personally in London on Thursday — and Cameron said Yes.

"Martin invited the prime minister to speak to the Conference of Presidents [a meeting of Parliament's political group leaders] on February 16. He accepted," the spokesperson told POLITICO.

That means Cameron will not speak before the plenary, but to a smaller gathering of leaders from the eight political groups, behind closed doors. Those leaders include Britain's most outspoken Euroskeptic, Nigel Farage of the U.K. Independence Party, and Marine Le Pen of France's far-right National Front.

"Finally! PM Cameron will be coming to @Europarl_EN," tweeted the liberal ALDE bloc, which is led by former Belgian prime minister Guy Verhofstadt. "The @aldegroup have been pushing for a debate for months."

The biggest parliamentary group, the center-right European People's Party, seemed disappointed he would not speak before the full house. "Cameron doesn't have any mandate to negotiate. The conference of presidents is a political meeting behind closed doors. All of this will lead to a political agreement but will it have a legal value?" asked MEP Alain Lamassoure of the EPP.

Britain's Conservative prime minister has pledged to hold an In/Out referendum on membership of the European Union by the end of 2017, but the vote is likely to take place in June, if he secures EU leaders' approval of the reform package on February 18. In that case, Cameron has promised to campaign to remain in the Union, which Britain joined in 1973.

The European Parliament has had no role in drafting the proposed U.K. deal which European Council President Donald Tusk sent to the other 27 EU leaders this week, but it will get the chance to debate and vote on Cameron's most contentious proposal, regarding migration from other EU countries.

MEPs want a bigger say on other parts of the draft proposal, including items that would undermine what little power they have, such as the proposed "red card" mechanism which would allow national parliaments to veto EU legislation.

"We cannot be squeezed out, they have to take us into account," said Elmar Brok, a prominent German MEP from the center-right European People's Party.

Top diplomatic advisors to EU leaders, known as "sherpas," meet in Brussels on Friday for the first technical session on the proposals since they were circulated among member countries on Tuesday. The Parliament will be represented by its secretary general, Klaus Welle, and Schulz's cabinet chief, Markus Winkler, and three leading MEPs.

All or nothing

In Schulz's meeting with Cameron in London on Thursday night, on the sidelines of a Syrian donor's conference, the German politician planned to warn the Tory leader about the assembly's influence on the decision-making process.

"When you can decide on one part, you can influence the whole," Schulz was going to tell Cameron, according to a Parliament source. "We disagree if we can't agree on the whole."

In the past, the Parliament successfully used the tactic of bundling various parts of legislation together as an "all-or-nothing" package for MEPs to approve or reject, for example when voting on whether to set up the European External Action Service.

Parts of the draft U.K. membership deal require the Commission to submit new legislation to the Parliament, while other parts can be decided with the unanimous approval of all 28 EU leaders.

Based on the first draft of the reform proposal, Parliament would get to vote on the "emergency brake" mechanism, by which Britain could ask the EU for clearance to suspend benefits for EU migrants, if its welfare system is being overwhelmed.

The European Commission's U.K. task force, led by British Eurocrat Jonathan Faull, has spent months looking for quick solutions to the U.K.'s reform wishes that do not have to go through the full legislative co-decision process.

According to a first draft of the speaking points for discussion by the sherpas this Friday, a copy of which was obtained by POLITICO, the Parliament attempted to push back against the red card system, believing it would sideline MEPs.

Among other points, the Parliament also objected to the prospect of non-eurozone members like Britain being able to demand a debate on decisions taken within the currency union. This would be "handing a veto to the U.K.," according to the draft.

"Parliament doesn't want to be sidetracked," said a source from ALDE.

However, not everyone in the Parliament wants it to have such a big role in negotiations. The European Conservatives and Reformist group — which includes the Tories — would prefer that MEPs endorse "the agreement as a whole" before the U.K. referendum. The Parliament should "commit itself unambiguously to implement it in full without qualification," the ECR said.