The disruption at Calais looks set to enter a second day as migrants continue to target lorries in a bid to cross into the UK.
There were chaotic scenes at the northern French port yesterday when striking ferry workers broke into the Channel Tunnel, forcing it to be shut.
Migrants tried to exploit the wildcat strike action by attempting to clamber aboard UK-bound lorries which had been forced to slow or stop due to queuing traffic on approach to the port.
Images this morning show migrants huddled at the side of the motorway while others are seen opening the back doors on lorries stuck in traffic.
More resources will be put into screening arrivals at Dover, immigration minister James Brokenshire has said, adding that extra French police officers are being deployed in Calais to deal with the problem.
While hundreds of Eurostar passengers were left stranded on both the English and French sides of the tunnel yesterday, the high-speed train company said all services are due to run as scheduled today.
All services from London are full, with rebookings being made for tomorrow, Eurostar said.
They advised passengers to allow plenty of time to check in.
The company tweeted last night: “We will be running as scheduled tomorrow, please arrive at least 45 minutes in advance for check in.”
Three trains stuck outside the tunnel on the English side yesterday had to return to St Pancras while other trains on the French side were taken back to Paris and Brussels.
Ferry services between Dover and Calais resumed yesterday evening after the strike ended, and appear to be running on time according to operators My FerryLink and P&O Ferries.
But a Port of Dover spokesman said Operation Stack – where freight traffic is held on the coastbound carriageway of the M20 in Kent – would remain in place due to the volume of freight traffic.
The travel problems yesterday come amid a worsening migrant situation near the Port of Calais where numbers camped there have swelled to more than 3,000 since April.
Aid workers have reported a “catastrophic” situation, with predictions that some 2,000 more migrants displaced from war-torn countries including Eritrea, Syria and Afghanistan could arrive over the summer.
Mr Brokenshire told the BBC: “It is hugely regrettable that we’ve seen these incidents occurring as a result of industrial action in France.
“We are putting additional resourcing into the port of Dover to enhance screenings and detections there so that we’re looking at this on both sides of the Channel.”
He added: “We have been advised the French authorities are sending further policing to deal with law and order issues, and we will be keeping in close contact with them in the hours ahead.”
The deputy mayor of Calais, Philippe Mignonet, reiterated calls from French politicians for the border to be moved from northern France to Britain.
Mr Brokenshire said: “These deployments of additional border force resourcing at Coquelles around the Eurotunnel terminal and also from our work at Calais, buttressed by further support at Dover, is about maintaining that safety and security and the integrity of the border, which is our absolute focus.”