Most photos taken of the negotiators seeking to reach an agreement over Iran's nuclear programme have EU foreign policy chief Federica Mogherini standing in the middle.

In a way, this is a victory in itself for the EU, demonstrating its ability to be a credible and respected party in what are arguably the most important diplomatic negotiations since the Camp David summit back in 1978.

However, the centrality of the EU in these negotiations does not necessarily mean that it will also reap the biggest rewards.

Russia, China, and the US are possibly more eager to get a share of the spoils and could push EU countries aside in what may be the biggest prize in a new “Great Game”.

This is why what happens following an agreement with Iran will likely have a great impact on the EU's diplomatic and geopolitical leverage in the years, if not decades, to come.

21st century Fashoda

European countries used to have much more clout in the Middle East.

In fact, just over a hundred years ago, in 1907, Britain and Russia even managed to agree on a partition of Persia into spheres of influence which effectively nullified the country's sovereignty.

In today's Iran, this is unlikely to be repeated, but the struggle to consolidate influence in the country will be just as fierce, turning Tehran into a 21st century Fashoda.

Instead of European countries calling the tune, today it is the US, Russia and China that appear to have the biggest stakes in Iran's future orientation.

For the US, achieving a breakthrough with Tehran will be a game-changer in addressing the multiple crises in the Middle East and should be seen in the wider context of America’s “pivot to Asia”.

This is because for China, Iran is important not just for its vast oil and gas supplies, but also because it is to be a lynchpin in its New Silk Road project.

Meanwhile, with Chinese influence extending into Siberia and across the plains of Central Asia, Russia does not want to see an overt Chinese presence in Iran that could extend into Turkey -another country with which Russia is seeking to develop better relations.

What's more, if Iranian oil makes it back to world markets, Russia stands to lose significantly owing to the similarity of both countries' chief export blends.

This is why Moscow is already jockeying for influence in Tehran, intending to unlock the sale of its S-300 missile system, and is seeking co-operation rather than confrontation with Beijing by pushing for Iranian membership of the Shanghai Co-operation Organisation.

Will Europe be heard?

None of this is to say that Europe does not have geopolitical stakes in Iran's future.

After all, it has great interest in cultivating Iran as a stabilising force in the Middle East, and relying on its influence in the region to address the war in Syria and Iraq. In addition, Iranian gas could have a significant impact on Europe's energy security in the long term, enabling it to diversify its imports and to lessen its dependence on Russian gas.

However, it is not evident that Iranians will prefer dealing with Europeans over the Chinese, the Russians, or even the Americans.

So far, Chinese and Russian businesses have been the true beneficiaries of Western-imposed sanctions regimes, and enjoy a first-mover benefit of sorts.

US companies will have to start from square one. But the fact that many Iranians have maintained strong ties with America since the 1979 revolution means US businesses could soon eclipse European interests.

Delicate dance

It is not a foregone conclusion that European countries will lose out when Iran opens up.

For starters, both China and the US will have to contend with the fact that cozying up to Iran will leave Saudi Arabia very unhappy, putting their ties with the kingdom in jeopardy.

Meanwhile, Israel is expected to give both the US and Russia a hard time following through on a possible agreement with Iran.

In the end, Iran itself may have second thoughts about getting itself entangled in a delicate dance trying to soothe Beijing, Moscow, and Washington all at the same time.

This makes it easier for European countries and businesses to strike up relations with Tehran, which are likely perceived as less threatening and bringing fewer diplomatic headaches.

It could be that standing in the middle of the photograph does pay off for Mogherini and for Europe, but only if she carefully watches what happens on her left and her right.

Willem Th. Oosterveld and Sijbren de Jong are analysts at The Hague Centre for Strategic Studies in the Netherlands