Russia will be the lead suspect in Friday morning’s attacks on the French rail network, as suspicions swirl that Vladimir Putin has been yearning for a chance to humiliate Emmanuel Macron.

French authorities had laid on a massive, high-tech security regime to defend the Olympics, with Reaper drones in the skies and AI-powered cameras on the ground to keep an eye out for any suspicious activity.

But Friday’s attack suggests they paid far less attention to key rail routes, which were sabotaged by old-fashioned arson rather than cyber-attacks, according to the latest reports.

There have been five incidents of damage to the SNCF rail network, all of them targeting electronic or signalling boxes.

The result was around 50 per cent of the trains in the north and east of France were not running as of Friday morning, while the high-speed TVG network was also paralysed.

France has not yet accused any group or state over the sabotage, but many will immediately point the finger at Moscow. Other possible suspects include terrorism groups, Left-wing extremists or environmental activists.

The head of SNCF has described the arsonists as a “band of lunatics” but gave no clues as to their identity.

Back in April Mr Macron, the French president, said he had “no doubt whatsoever, including in terms of information,” that Russian leaders were planning to disrupt or damage the event.

Around the same time an aide to Mr Macron warned: “There is a hardening from Russia, which we have been seeing for several months.”

France’s diplomatic and military support for Ukraine has put it in the crosshairs of a new Russian campaign against Europe known as “hybrid warfare,” which involves sabotage, arson, cyber-attacks and other attempts to destabilise Western democracy.

And there is already a precedent for Russia being suspected of arson attacks on businesses and key infrastructure in Europe.

In May, when a mysterious fire broke out at the Diehl arms factory in Berlin, German investigators initially ruled it an accident. But they have since received intelligence from a Nato member state which strongly suggests it was actually a Russian sabotage attack.

In the previous month, pro-Russian arsonists targeted a business with commercial links to Ukraine in east London. The British Government expelled Russia’s defence attache in response to the attack.

Jérôme Poirot, terror expert for RMC-BFMTV, said: “We know that Russia and other countries want to interfere with the Olympic Games. There may be a plan in place to prevent the opening ceremony.”