German chancellor Angela Merkel has warned that European Union states negotiate better deals than those outside of the union as she urged the UK to remain a member.
The German leader said she wants the UK to stay "part and parcel of the EU", adding it is in the interests of both Germany and the UK.
Speaking during a news conference in Berlin, she said Germany and the UK work well together when lobbying the EU.
In comments translated by the BBC, she said: “We work well together with the UK, particularly when we talk about new rules for the EU.
“We have to develop those together with the UK and whenever we negotiate that, you can much better have an influence on the debate when you sit at the bargaining table, and you can give input to those negotiations, and the result will then invariably be better rather than being outside of the room.”
She stressed the importance of the free movement of goods, people and capital, adding countries outside the EU “will never get a really good result in negotiations”.
She added: “It would not only be in our interest but it could also be in the interest of Britain when it can bring its whole political weight to the negotiating table as part and parcel of the EU.”
It comes after Spain’s prime minister warned of negative consequences for the UK if it votes to leave the EU.
Mariano Rajoy said a vote to leave the EU would mean British citizens would lose the right to move freely around Europe.
He pointed to the more than 400,000 British citizens who live and work in Spain, compared with 100,000 Spanish citizens in the UK.
Speaking to Spanish news agency EFE, Mr Rajoy said the UK leaving would be "negative for everybody, for the United Kingdom, for Spain, and for the European Union".
He said: “But, above all, it would be very negative for British citizens: the European Union is based, ever since its foundation, on the principles of freedom of movement of people, goods, services, and capitals.
“If the United Kingdom left the European Union, it would be very negative for everyone and from every perspective.”
The Dutch prime minister Mark Rutte has cautioned Brexit campaigners over their promise of a points-based immigration system, warning it would be met with a tit-for-tat response from other European countries.
He told BBC News: “It would be unavoidable, inevitable for us and I think for many of us in Europe to follow the same proposals to implement a points system also in the rest of the European Union.
“So, you would get a race to the bottom and that’s exactly what you don’t want.”