Crunch time on EU as Cameron meets Merkel for referendum talks

David Cameron's mission to reform the EU treaty was given a significant boost today, as German Chancellor Angela Merkel said: "Where there is a will, there is a way".

The Prime Minister was in Germany for the latest part of his European charm offensive - though earlier in the day, in Poland, his views were not so well received.

Leaders in Poland are upset by plans to curb benefits for foreign workers.

ITV News Europe Editor James Mates reports:

German Chancellor Angela Merkel refused to rule out treaty change as she met with David Cameron in Berlin to discuss his plans to renegotiate the terms of the UK's membership of the European Union.

Mrs Merkel said: "Of course we have the desire to work very closely together. We would like to be a part of the process that is going on in Great Britain at the moment and we would like to be a constructive partner in this process.

"I have also said wherever there is a desire there's also a way and this should be our guiding principle here as well."

David Cameron has met with Polish Prime Minister Ewa Kopacz in Warsaw as he continues his tour of Europe to lay out his plans for renegotiating the terms of the UK's membership of the European Union.

They agreed on issues including making Europe more competitive by strengthening the single market, cutting back red tape, ensuring fairness between euro-ins and euro-outs and more subsidiarity, respecting the sovereignty of Member States, a Downing Street spokesperson said.

On immigration and welfare, Kopacz also welcomed Cameron's "commitment to respect the principle of free movement."

"They agreed that there were issues concerning the interaction between free movement and national welfare systems that should be discussed further, the spokesperson said.

The pair also discussed the situation in Eastern Ukraine and agreed that the EU's existing sanctions must remain in force until the Minsk agreements are fully implemented.

David Cameron is to round off his whirlwind tour of major European leaders with a crucial meeting with German Chancellor Angela Merkel.

The Prime Minister is looking to build support for his plans to renegotiate the terms of the UK's membership of the EU, and he'll need the agreement of the German premier if he is to have any hope of success.

However, there has been little sign of enthusiasm for treaty change. France and Germany have reportedly agreed that closer integration of the eurozone countries can be achieved without altering treaties - potentially reducing Britain's leverage.

This morning Mr Cameron will be in Warsaw for talks with Polish counterpart Ewa Kopacz, before heading for Berlin to see Mrs Merkel.

The Prime Minister has met French President Francois Hollande in Paris to discuss potential changes to the EU treaty which he says could benefit both countries.

Describing France as an "essential and valued partner of Britain", David Cameron said the two countries might have different priorities, but similar aims for the future, and said he hoped they could reach an agreement - including on issues such as tackling extremism and climate change.

Foreign Secretary Philip Hammond has warned that the British people are likely vote to leave the EU unless there is substantial reform in Brussels.

He spoke as David Cameron began a whistlestop tour of Europe, meeting political leaders in a bid to build support for change.

ITV News deputy political editor Chris Ship reports:

David Cameron said the UK and the Netherlands were "old friends and like-minded allies" as he met with Dutch prime minister Mark Rutte in The Hague.

Among the issues to be discussed will be European reform, the need for flexibility and the need to focus on growth and jobs, Mr Cameron said.

The Hague is the first of four European capitals the Prime Minister is visiting on a whirlwind tour to discuss his plans to renegotiate the terms of the UK's membership of the European Union with key leaders.

Later Mr Cameron will travel to Paris in France where he will meet with President Hollande.

The Government will not win its referendum on Britain's continued membership of the European Union unless there is "substantial" reform in Brussels, Foreign Secretary Philip Hammond has warned.

Speaking to the BBC, Hammond said: "The Prime Minister is very clear in dealing with European counterparts that if we are not able to deliver on these big areas of concern that the British people have, we will not win the referendum when it comes.

"We expect our European Union partners to engage with us in delivering a package that will enable the British people to decide that Britain's future is best delivered inside the European Union.

"We expect that some of our partners will adopt a hard line at the start of the negotiations - that's how negotiation works - but we are very confident that, over the course of the summer and perhaps onwards through the winter, we will be able to negotiate a substantial package of reform which will address the concerns that the British people have."