Baur and Merabet – who are known to police as Muslim radicals having converted to Islam while in prison on drugs charges – are now in a high security prison after a raid on their apartment in Marseille appeared to confirm their twisted intentions.

Agents from the DGSI, France’s domestic intelligence service, found weapons in the property along with TATP – explosives often used by jihadis. They were arrested as part of an investigation into ‘criminal association and breach of arms legislation in connection with a terrorist enterprise’.

Police also found a video made by the pair in which they stated their allegiance to IS together with a Le Monde newspaper front page showing Mr Fillon’s photograph. It was apparently part of a photomontage which included a machine gun, an IS flag, ammunition and the words ‘The Law of Talion’ – a reference to a fictional character in a violent videogame.

Interior Minister Matthias Fekl said the planned assassination was due to be carried out in the ‘next few days’. France is already on high alert following a series of atrocities carried out by Muslim fundamentalists.

With a French presidential election about to take place, an estimated 50,000 police and soldiers will be deployed around France for each round of the two votes, due to take place on April 23 and May 7.