Negotiators gathered on Thursday in Lausanne, Switzerland, for what could be a crucial round in the talks over the future of the Iranian nuclear programme.

The largest delegations, from the United States and Iran, were headed by Secretary of State John Kerry and Foreign Minister Mohammed Jawad Zarif.

It is expected that foreign ministers from the other nations taking part in the talks could travel to Switzerland if a final deal appears imminent. At this stage, it seems that the details of a possible deal will be worked out only in the coming months.

While the basic framework on limiting Iranian uranium enrichment and the development of its plutonium reactor has already been worked out, there remain significant differences between the sides.

The main disagreements are over Iran's demand that all sanctions be removed once it signs a comprehensive deal, and its refusal to curb nuclear research under the terms of the agreement.

The Israeli government's assessment is that the most likely outcome of this weekend's talks will be a very general outline of an agreement, perhaps just a verbal "statement of understanding", which will be enough to keep the talks going until the next deadline at the end of June.

With the personal relationship between President Barack Obama and Prime Minister Benjamin Netanyahu at a nadir, Israel is looking to other members of the P5+1 groups, particularly France and Britain, to block a "bad agreement" with Iran.

Strategic Affairs Minister Yuval Steinitz and Mr Netanyahu's national security adviser Yossi Cohen visited Paris and London this week in an attempt to urge their counterparts to oppose the impending deal.

Foreign Secretary Philip Hammond will have heard a very similar message last weekend from the Saudis when he made a surprise visit to Riyadh.

The Israeli and Saudis are frustrated over what they see as an over-eagerness on the part of the Obama administration to sign an agreement with the Iranians, seemingly at any cost.

On Monday, Prime Minister David Cameron discussed the Iranian issue over the phone with Mr Netanyahu when he called to congratulate him on his election victory.

France and Britain, along with Germany and the EU as a whole will have to give their blessing to any deal with Iran; not only as members of the P5+1 group, but also to allow the easing or removal of sanctions on Iran.

Since the Senate in Washington is expected to oppose a removal of the American sanctions, one alternative course of action is to try to start by removing European sanctions on Iran's oil trade and its access to the SWIFT banking network.