The public is being warned a contingency plan is in place to protect them as up to 900 firefighters go on strike.
The walkout in Essex is over proposed cuts, staffing levels and working conditions.
The county's fire and rescue service says more than one hundred firefighters are still working.
More top news
Sunny this evening, then dry overnight. There is the risk of thundery showers for Kent tomorrow morning, then sunny spells by the afternoon
Sunshine to end the day then dry tonight. Tomorrow will be mostly dry and feeling fresher with the risk of a heavy shower in the afternoon
The video, obtained by ITV News, shows scores of migrants desperately trying to board lorries in a restricted area within the tunnel.