BRUSSELS (Reuters) – The European Parliament would not block a deal to help keep Britain in the European Union but may not back it fully, its president said on Tuesday, as British Prime Minister David Cameron prepared a final push to secure support for the deal.

Cameron must hammer out differences with fellow EU leaders at a summit on Thursday over a plan to reform Britain’s relationship with the European Union. If Britain subsequently votes to stay in the EU, the European Parliament would still need to approve key elements of the deal.

“I can give you a guarantee that the European Parliament will, immediately after the referendum to stay in (Europe), legislate on the proposal of the Commission,” Parliament President Martin Schulz told reporters after his meeting with Cameron.

“But to be quite clear, no government can go to the Parliament and say: this is our proposal, can you give a guarantee about the result. This is not possible in a democracy.”

Schulz stressed that the role of the parliament was not to block a deal, responding to Nigel Farage of the anti-EU UK Independence Party, who said that the European Parliament would veto its terms.

“The European Parliament doesn’t have a veto, I completely refuse this rhetoric,” Schulz added.

Cameron met Schulz and lawmakers from the three main parties on Tuesday, before holding talks with European Commission President Jean-Claude Juncker.

An initial plan to meet the leaders of all the European Parliament’s party blocs was cancelled — allowing Cameron to avoid a confrontation with his eurosceptic domestic critic Farage.