Lorries are once again being parked on the M20 as police reintroduced emergency closures while Channel Tunnel trains suffered further disruption.
Kent Police reinstated Operation Stack - where HGVs are queued on sections of the motorway in Kent to avoid gridlock on the county's roads - with junctions eight to nine closed to non-freight traffic.
A police spokesman said the measure had been enforced because of the large amount of freight traffic heading towards the Port of Dover and Eurotunnel, along with "continued disruption" in Calais.
Eurotunnel said its passenger services were disrupted, with waiting times of up to an hour in both directions due to what the company described as "an incident on the terminal".
The firm said: "We sincerely apologise for the inconvenience this will cause to your journey."
The port said it remained "open for business" with P&O operating full services to Calais and DFDS Seaways to Dunkirk.
In a statement it said: "The port and the ferry operators are together working hard to serve all customers travelling to and from the continent. We apologise for any delays or inconvenience as a result of traffic congestion."
The reinstatement of Operation Stack comes just days after it was lifted following disruption caused by "migrant activity" and wildcat strikes by ferry workers in France in protest at job cuts.