The video appears to suggest that the Paris attack could be inspired by the Islamist murder of a British serviceman in London.

Anti-terrorism investigators now say they have “high quality images” of a “tall, athletic bearded man” aged about 30, possibly of North African origin, praying near the spot where he attacked the 23-year-old soldier from behind with a knife or a box-cutter on Saturday. He then fled into a crowded train station and is still at large.

“He was filmed praying near where the attack took place. After the attack he can be seen leaving the shopping centre of La Défense (business district),” a source close the investigation told Le Parisien.

The soldier, Cédric Cordiez, survived the midafternoon attack and was discharged from hospital this morning but is said to be “traumatised” by the stabbing.