It is highly likely that David Cameron’s British referendum on membership of the European Union will take place at some point in 2016. Despite the fact that the respective “leave” and “remain” campaigns have yet to begin in earnest, a host of world leaders, including Barack Obama and those of most European and many commonwealth countries, have been privately urging David Cameron and his Conservative party against a “Brexit”.

Despite the economically illiterate central tenets of the leave campaign – that a Brexit will somehow enable Britain to “go global” – it is striking that very few countries, if any, have been campaigning for Britain to leave the EU. This is perhaps because a significant number of countries have committed time and resources to negotiating trade agreements with the EU, of which Britain is such an important part.

Thanks to the hard work of the many British civil servants in Brussels, the EU is now negotiating fully fledged free-trade agreements with Australia, New Zealand, Japan and the US. A deal with Canada is already concluded. The notion that these countries would relish the possibility of negotiating a separate trade agreement with Britain, or indeed that Britain would secure preferential trade deals by leaving the world’s largest common market, is absurd.

British people should reflect on the fact that the only leader who would stand to gain from a British withdrawal from the European Union is Vladimir Putin. There are several reasons for thinking this.

First, geopolitics. Undoubtedly, the destabilisation of the EU is a foreign policy priority for the Russian president. The EU and the values it stands for – fundamental rights, media freedom, equality and the rule of law – are the antithesis of the Eurasian Union that Putin wishes to build. A British exit would weaken Europe militarily and politically, while providing far-right nationalists across Europe with an example to follow. Far-right political parties in France, Denmark, Sweden and elsewhere are already asking why they can’t have the same, semi-detached arrangement as Britain, along with a referendum too.

Second, much-needed EU sanctions against Russia are more likely to be dropped if Britain left. Already the resolve of some EU countries has weakened. The UK has, correctly in my view, been one of the strongest advocates in the European council for tough sanctions against Russia, for its illegal invasion and ongoing occupation of eastern Ukraine.

A third reason why Putin would relish a British exit from the EU is because Britain has strongly supported an independent European energy strategy. It is economically and strategically vital for Putin that EU countries remain reliant on Russia’s vast supplies of gas and oil, which he has consistently used as a foreign policy instrument. Even under this Conservative government, the UK has remained broadly supportive of ambitious EU targets for renewables, energy security and energy efficiency. Via the state-owned gas company Gazprom, Moscow continues to channel millions of dollars to lobbyists across Europe, who are paid to obstruct and impede plans spearheaded by the European commission for a so called “energy union”, the main purpose of which is to boost independence from Russian gas.

It is no coincidence that the European parliament’s contribution to this strategy was sabotaged in December by the far-right ENF group of MEPs, led by Marine Le Pen, whose Front National party has allegedly received funding from Moscow. Le Pen has proudly visited the Kremlin many times and, along with Nigel Farage, openly celebrates Russia’s “achievements” and Putin’s “strong leadership”. Ukip MEPs and their far-right bedfellows have consistently voted to oppose EU sanctions against Russia in the European parliament.

Le Pen has described a possible Brexit as “like the fall of the Berlin Wall”. Indeed, she told a British newspaper last month that “Brexit would be marvellous – extraordinary – for all European peoples who long for freedom.” I have no doubt Putin agrees with her on this.

This is set to be a challenging year. Instead of focusing on the refugee crisis, Russian expansionism and the security threat posed by Isis, many hours of valuable meeting time in Brussels will be taken up by David Cameron’s desire to further detach Britain from the EU, which could ultimately prove to be a flawed exercise in domestic party management.

Many British Conservative Eurosceptics recently argued for military intervention in Syria on the grounds that Britain should stand shoulder to shoulder with her allies, yet they and Ukip angrily dismiss calls from Britain’s allies to stay in the EU as “interfering” with British affairs. This is hypocrisy. It’s time they face up to the fact that the only world leader supporting a British exit from the EU is Vladimir Putin.