Now that Britain has left the European Union, the French president, Emmanuel Macron, has moved swiftly to put French nuclear weapons front and centre of EU defence policies. In an hour-long speech on Friday to L’École de guerre (School of War) in Paris, the French president called for a European dialogue about defence and deterrence based on France’s force de frappe of nuclear weapons launched by air and submarine, and invited other EU states to participate in exercises by his country’s nuclear forces.

This is the post-Brexit revival of a vision held by successive French leaders, who itched to establish EU defence policies that would rely on European nuclear weapons rather than the US and Nato. For decades, this aim was marginalised by other EU members. Brexit, Donald Trump and Vladimir Putin have emboldened Macron to put it back on the table – and this time he is getting more attention.

French ambitions to provide the nuclear deterrence role in an integrated EU defence policy had previously been thwarted by Germany and the UK, which were more closely embedded with Nato and considered the US to be more reliable. Those governments have always been wary of France’s nuclear plans, although David Cameron eagerly entered into the 2010 Teutates treaty with France that enabled both nuclear-armed nations to share research facilities and cooperate on technology. The main purpose of Teutates, however, was to help both countries share the financial burdens of maintaining their nuclear status.

Everything has now changed: with Brexit, the UK no longer has a voice in the EU, while Germany has become increasingly anxious about the nuclear policies of President Trump. Last week, a senior member of Angela Merkel’s CDU party in the Bundestag, Johann Wadephul, publicly raised the “question of French nuclear weapons as an element of European deterrence”. The remarks appear to have been coordinated with France in advance of Macron’s speech. By characterising the role of French nuclear forces in terms of European security, stability and “proper deterrence”, Macron attempts to provide reassurance. Recognising the fears engendered by a reinvigorated nuclear arms race between the US and Russia in their efforts to build more, “usable” nuclear weapons, including a new generation of enhanced medium-range missiles, Macron promised that “France will never engage in nuclear battle”.

Previous attempts to portray France’s military forces as “European deterrents” had come up against a locked door, bolted on the inside by the UK and Germany. Now, with Nato in disarray, the UK marginalised, and Putin and Trump busy competing with each other on various fronts, Macron clearly hopes that other European countries are ready to welcome French nuclear weapons as guarantors of regional security.

Macron also hopes to legitimise France’s nuclear weapons and policies in advance of the important review conference of the 1968 non-proliferation treaty (NPT) in April. He and the other nuclear-armed governments know they will face strong criticism for undermining the NPT and failing to comply with its fundamental nuclear disarmament obligations. The newest tool in the non-proliferation regime is the 2017 treaty on the prohibition of nuclear weapons, which was negotiated in the UN general assembly after the 2015 NPT conference failed.

This landmark treaty prohibits all activities associated with acquiring, possessing, deploying and using nuclear weapons. It was adopted in 2017 by 122 parties to the NPT, of which 80 have signed in the first two years, including EU members Ireland and Austria.

Even before the treaty enters into full legal force, in France and other non-signatory countries, its objectives and provisions are leading to steps taken by municipal authorities and financial institutions to divest from nuclear weapons and promote nuclear disarmament. Macron’s references to this treaty in his speech are dismissive, but they also demonstrate his anxiety about its impact on France’s nuclear establishment – France previously opposed the NPT before signing up to it in 1992.

Beset by yellow vests and economic woes, Macron desperately needs a big idea to distract from his domestic challenges, and hopes that the vision of uniting Europe under a French nuclear umbrella will work. It won’t.

Macron is right to warn that nuclear risks are increasing, but his answer of France supplying Europe with nuclear deterrence flies in the face of reality. Theorising about deterrence, the French president tries to avoid the inescapable fact that relying on nuclear weapons for deterrence requires preparedness, policies and doctrines to actually use them. In a survey in January by the International Committee of the Red Cross, 81% of French respondents said that the use of nuclear weapons was never acceptable. Macron’s promise not to engage in nuclear battle is disingenuous. Possessing and deploying nuclear weapons are the precursors for nuclear use, and also heighten the risks of miscalculation, mistakes and accidents, with the obvious catastrophic consequences that would follow.

Meanwhile, the municipal government of Paris has joined other cities and countries around the world in taking practical steps to end nuclear-related investments and comply with international laws prohibiting activities that could lead to nuclear weapons ever being used again. If Macron really wants to contribute to European security, he should ensure that France does so too.

• Dr Rebecca E Johnson is director of the Acronym Institute for Disarmament Diplomacy