As many as 1000 migrants have been involved in a plan to storm the Calais entrance to the Channel Tunnel in a bid to reach England, some armed with iron bars and hammers. The A16 road into Calais had to be shut for an hour as police fired tear gas at the crowd to drive them back.

Vigilant locals have taken to the Facebook group ‘Les Calaisians en Colère’ (Calaisians are Angry) to warn that gangs of around 50-60 migrants at a time were working to bring traffic to a standstill as their accomplices attacked the tunnel.

“An attack on the tunnel by the illegal immigrants is in progress!” they posted “Be vigilant if you go to this area, especially around avenue Roger Salengro where groups of 50 to 60 illegal immigrants have been sighted…”

“WARNING! There are reports from reliable sources that a group of six or seven migrants are running around with iron bars, stones and hammers.”

The group also posted several videos of migrants congregating at roadsides, attempting to halt traffic.

The activity appears to have been going on for at least twenty four hours – last night the group posted a video showing drivers narrowly avoiding having an accident, as they swerved around mattresses and a tree branch which had been left in the road.

Commenting, Vanililaslise Short wrote: “…I was present, they are everywhere and it’s really not nice to be in the middle of hell!”

Sophie Lesuisse added: “They are everywhere…the entrance to the tunnel and the highway closed to the city.

Marine Canu replied: “Yes it’s heated, I just passed this driving. It’s super scary!”

Martial Lamoureux said: “All of this risks ending up in a pool of blood!”

Others reported activity elsewhere. Choubibi Bidoubidou commented: “I just found myself in the middle of the full onslaught of hundreds of migrants on the A16.

“Clashes also with CRS [French riot police] and tear gas. Very, very dangerous – take care.”

The A16 was shut for an hour both ways, France3 has reported, as the CRS tried to move on between 800 and 1000 migrants who had congregated there to block traffic.

“Approaching the tunnel, many migrants have tried by all means to slow traffic to board trucks, blocking roads and by removing metal grids,” the prefecture of Pas-de-Calais said.

“It is a phenomenon encountered during the days of heavy traffic (especially mid-week and some weekends) in the run-Channel devices. The migrants try to slow traffic to break into the trucks heading to Britain,” he added.

In a now-familiar scene, police deployed tear gas at the migrants, who responded by hurling projectiles.