Lorry drivers planning a protest about the migrant crisis in Calais are "in it for the long haul" and will stand their ground until they see action to dismantle the Jungle camp, a trade association has warned.
Shopkeepers, police, unionists and farmers are set to join hauliers in calling for the northern section of the camp at the French port to be demolished.
The protest, expected to take place on roads around the town on Monday, is likely to disrupt British cross-Channel travellers.
Talks took place between French organisers and French interior minister Bernard Cazeneuve on Friday.
Pressure has been growing on the French authorities to tackle the problem, which has seen the camp swell in size in recent months.
Despite efforts to reduce numbers by dismantling the slum's southern section earlier this year, up to 9,000 migrants from countries including Sudan, Syria and Eritrea are living there in squalor.
The Road Haulage Association (RHA) said it was disappointed that "despite assurances that the action by Calais hauliers would take the form of a go-slow, this now appears not to be the case".
RHA chief executive Richard Burnett said the organisation has spoken to a representative of the French road transport union, the FNTR, who said that on Monday at 7.30am (local time) lorries and tractors will be gathering at Dunkirk to the north of Calais and Bolougne to the south.
"Both groups will then travel along the A16 towards Calais, converging at the Eurotunnel exit," he said.
The RHA said 200 French farmers are joining in the protest, angry at migrant action that has resulted in destroyed crops and extensive damage to farms in the area.
Mr Burnett added: "It seems certain that traffic crossing from the UK will find it almost impossible to leave the port as access to the A16 is denied.
"The inevitable repercussions of this will surely mean that the authorities on this side of the Channel will have no alternative but to deploy Operation Stack. This will bring yet further misery to hauliers bound for mainland Europe and of course for the people and businesses of Kent."
Mr Burnett said: "It appears that the proposals made by the minister were not enough to placate local Calais businesses and hauliers. We have been told that those taking part in the protest are in it for the long haul and they will stay there until they see action to dismantle the camp."
The Freight Transport Association (FTA) said it had spoken "at length once again" on Saturday morning with David Sagnard - one of the protest organisers - and said he told them he is adamant that the blockade will go ahead as planned.
People traffickers are reported to be going to extreme lengths in Calais in their efforts to reach the UK, with reports of vehicles being torched, petrol bombs thrown and trees being cut down to block roads before drivers are threatened with chainsaws and machetes.
Gangs are paid thousands of pounds by vulnerable people to get them to Calais, from where some are smuggled to Britain to work to pay off huge debts to people traffickers.