The European Commission (EC)’s president says he will do all he can to keep Britain in the European Union (EU), but not at the expense of changing basic treaties, as requested by the UK.

Jean-Claude Juncker said on Monday that the EU and Britain needed each other, adding that a British exit from the 28-nation bloc would not be in the interest of either side.

“I’m in favor of a fair deal for Britain,” said Juncker, adding, “I can’t believe in a European Union without Britain.”

Juncker said the EU is ready to work with the UK to ensure that the provisions of a treaty that considers no limit on migration from one EU state to another are not violated.

UK Prime Minister David Cameron (shown below) has said he wants to be able to limit migration from other EU countries.

Juncker said the treaty is a red line.

“I’m not ready to give up freedom of movement for workers... You can’t change the treaty,” he said.

Cameron’s Conservative Party, which is under growing pressure from the anti-EU UK Independence Party (UKIP), has said that it will try to cap immigration if re-elected in the May general elections.

Cameron is calling for a renegotiation of Britain’s EU membership terms, saying that the reforms are crucial to persuading Britain to stay in the bloc. Cameron has also vowed to hold an in-out vote on the country’s EU membership by 2017.

YH/HJL/HMV