Britain, the US, Germany, and France issued a joint response to the poisoning of Sergei Skripal and Yulia Skripal on Thursday afternoon, condemning Russia for the "first offensive use of a nerve agent in Europe since the Second World War".

But on Thursday morning and through Wednesday France had initially appeared more hesitant to line up behind Theresa May’s version of events, with Emmanuel Macron’s government taking a more careful approach.

On Wednesday Benjamin Griveaux, a spokesperson for the country’s government, said it was too early to decide on retaliatory measures against Russia, as its involvement was yet to be proven.

“We don't do fantasy politics. Once the elements are proven, then the time will come for decisions to be made,” he told a press conference shortly after Theresa May announced she would be expelling Russian diplomats over the poisoning.

The response apparently raised eyebrows in Westminster and elsewhere, where Theresa May’s analysis and approach has received stronger support. Anders Fogh Rasmussen, the former Nato chief, told the BBC that “anything short of full solidarity with the UK will be considered a victory by the Kremlin”.

The French government then put out another statement, this time as an “Elysee source”, which said: “France's solidarity with the UK is unquestionable.

“President Macron denounced as early as Tuesday the Salisbury chemical attack as unacceptable and assured Prime Minister May the UK had France's full support. Both leaders will discuss the matter yet again this Thursday.

“Since the beginning of this week, the UK has briefed its allies thoroughly, and France in particular, that it was highly likely that Russia was responsible for the attack.”

Saying you’ve been told something was highly likely, is of course, not the same as saying you believe it is true.

The French statement also contrasted with what the White House was saying at the time, with an unequivocal condemnation of what it said was Russian involvement: “The United States shares the United Kingdom’s assessment that Russia is responsible for the reckless nerve agent attack on a British citizen and his daughter,” a spokesperson said.

Donald Trump's administration is widely regarded as being close to Russia, so why were they ahead of France in condemning the attack? Key to understanding the different French response is the strategy taken by Emmanuel Macron to Russia and Vladimir Putin and the background to the two leaders’ relationship.

Mr Macron has always been keen not to isolate Russia on the international stage. He is making his first presidential trip to Russia in May, and has engaged directly with Mr Putin over Syria in a way that some other Western leaders have not, asking the president to help open humanitarian corridors and mooting the return of peace talks.

Britain's Prime Minister Theresa May addresses the House of Commons on her government's reaction to the poisoning of former Russian intelligence officer Sergei Skripal and his daughter Yulia in Salisbury (Parliament TV handout via REUTERS)

Last month the two leaders had a comprehensive discussion over the telephone in which they pledged to cooperate more closely, including on Syria. They have also tried to put the Ukraine conflict behind them. Mr Putin visited France in May of last year.

Diplomatically, preventing a leader from becoming isolated is a fairly standard approach to preventing the escalation of a conflict. But there are also increasingly important economic ties between the two countries, too.

Russian state media outlet RT reported earlier this month that trade between the two countries is booming, having risen by around a fifth in 2017 despite sanctions. France buys minerals from Russia, while Russia buys chemicals, machinery, and food from France.

Skripal attack aftermath – in pictures Show all 15 1 /15 Skripal attack aftermath – in pictures Skripal attack aftermath – in pictures Scene of attack Members of the emergency services in hazard suits fix the tent over the bench where Sergei and Yulia Skripal were found unconscious on a park bench in Salisbury in March 2018. Getty Skripal attack aftermath – in pictures Victim - Sergei Skripal The retired Russian colonel and former double agent for MI6 was in a critical condition in hospital for more than two months after being exposed to novichok in Salisbury. He was given refuge in the UK after being jailed in Moscow for treason. Mr Skripal came to Britain as part of a high-profile “spy swap” in 2010 in which four men were exchanged for ten Russian "sleeper agents" in the US. In this image he is speaking to his lawyer from behind bars in Moscow in 2006. AP Skripal attack aftermath – in pictures Victim - Yulia Skripal Yulia Skripal was struck down by a novichok poison alongside her father Sergei. Facebook Skripal attack aftermath – in pictures Scene of attack A police officer stands guard outside a branch of the Italian chain restaurant Zizzi where the pair dined at before falling ill. It was boarded off whilst investigators worked on the building and later found traces of the chemical weapon within it. AFP/Getty Skripal attack aftermath – in pictures Scene of attack Large areas of central Salisbury were cordoned off by police following the discovery of the Skripals. Traces of nerve agent were also found in The Mill pub. PA Skripal attack aftermath – in pictures Victim - Nick Bailey Detective Sergeant Nick Bailey, rushed to the aid of the Russian ex-spy and his daughter who were targeted with a nerve agent. He was hospitalized after aiding them and didn't leave until three weeks after the attack. Wiltshire Police/Rex Skripal attack aftermath – in pictures Police investigation - Skripal’s home Police believe they were poisoned at home, and detectives found the highest concentration of novichok on the front door of Mr Skripal’s house. Getty Skripal attack aftermath – in pictures Theresa May visits scene of attack Britain's Prime Minister Theresa May spokes with Wiltshire Police's Chief Constable Kier Pritchard near where the Skripal's were found. Britain expelled 23 Russian diplomats over the nerve agent poisoning and suspended high-level contacts, including for the World Cup on March 14. Theresa May told parliament that Russia had failed to respond to her demand for an explanation on how a Soviet-designed chemical, Novichok, was used in Salisbury. AFP/Getty Skripal attack aftermath – in pictures Skripal days before attack Sergei Skripal days before he was exposed to Novichok, that has left him fighting for life. ITV News Skripal attack aftermath – in pictures Police investigation - military involvement British soldiers were deployed soon after the attack to help a counter-terrorism investigation into the nerve agent attack. One of the places they were asked to help out with was Skripal's home and it's surrounding. They were asked to remove a vehicle connected to the agent attack in Salisbury, from a residential street in Gillingham. AFP/Getty Skripal attack aftermath – in pictures Police investigation Personnel in protective coveralls and breathing equipment cover an ambulance with a tarpaulin at the Salisbury District Hospital. AFP/Getty Skripal attack aftermath – in pictures Police investigation The investigation extended to the grave of Sergei Skripal's son Alexander in London Road cemetery. Getty Skripal attack aftermath – in pictures Police investigation The Counter Terrorism Policing Network requested assistance from the military to remove a number of vehicles and objects from Salisbury. EPA Skripal attack aftermath – in pictures Home Secretary visits scene of attack Home Secretary Amber Rudd visited the scene of the nerve agent attack at the Maltings shopping centre on 9 March. Getty Skripal attack aftermath – in pictures Yulia Skripal speaks for the first time Yulia Skripal, speaking for the first time, said she felt lucky to have survived the nerve agent attack in Salisbury which left her fighting for life. Ms Skripal said her life had been “turned upside down” by the assassination attempt. But the Russian national added she hoped to return to her homeland one day, despite the Kremlin being blamed for the attack. Reuters

Russian ambassadors are also keen to note that French investment in the Russian economy is growing, having reached more than $14 billion, while Russia's direct investment in France is $3.2 billion, according to figures put out on RT.

More straightforwardly, French scepticism of the claims of British intelligence is nothing new, as anyone who remembers the run-up to the Iraq war will know. But for France, the stakes of alienating Russia are simply higher.

Britain’s economic relationship with the country mostly involves Russian big money coming to London, a relationship that doesn’t seem likely to be endangered by anything Theresa May says about Vladimir Putin. This is arguably not the case for France, explaining its initial caution – even if after international pressure, it lined up behind its allies.