Germany’s Merkel insists Britain remain in EU.

German Chancellor Angela Merkel insisted Monday that Britain remain in the European Union, saying it was a vital gateway to the world for continental nations.

Prime Minister David Cameron has said he will hold an in-or-out referendum on Britain’s membership of the EU in 2017 if he wins a general election in May, amid tensions over immigration reform.

Foreign Secretary Philip Hammond warned Friday that Britain was prepared to walk away from talks with EU partners over the divisive issue, adding that such an outcome could influence voter sentiment on exiting the bloc.

Merkel earlier this month warned Cameron he was approaching a “point of no return” with the EU over immigration.

But she insisted Monday that Britain’s place in the union was vital and said she would do “everything I can” to ensure it remained a member.

“What the British decide to do is something they have to decide for themselves, and they certainly will not listen to what others have to say on this,” the German chancellor said in Sydney, following her attendance at the Brisbane G20.

“But it is most important for us to have the United Kingdom in the union, because it’s a country that is open to the rest of the world.”

Merkel said Britain had a different perspective on the United States and the Asia-Pacific region to continental Europeans, who she said “sometimes think if we only look at ourselves on average, that’s sufficient and we’re important enough”.

“This is why we need Britain… so we don’t lose sight of what’s happening in the rest of the world,” she said.

“Britain is helping us not to see it in quite this way, so I’ll do everything I can. I hope we will be able to persuade them to remain members of the European Union.”