Queuing lorries park on the M20 under Operation Stack
Strike action by French fishermen has led to the implementation of Operation Stack on the M20 in Kent to ease jams caused by lorries going to Dover port.
It follows blockades which closed the ports of Calais, Dunkirk and Boulogne.
Ferry operators P&O and SeaFrance said on Wednesday evening that the blockage by French fishermen has been lifted.
But Operation Stack, where lorries park on the M20 during cross-Channel delays, is set to remain in place on Wednesday night and in the run-up to the weekend.
A statement from Kent Police on Wednesday evening said the force was "issuing a strong message" to travellers not to attempt to get to Dover port without ensuring services are running again.
At 1700 BST, it was estimated that about 1,200 lorries were queuing on the M20.
Up to 3,320 vehicles can be stacked on the coastbound carriageway between the two closed junctions, the statement said.
The coastbound part of the M20 has been closed between junction eight for Leeds Castle and junction nine for Ashford West.
The carriageway is being used to park lorries before directing them through to either the Channel Tunnel or Dover.
Brian Rees from P&O Ferries explains the consequences
Other traffic is being diverted from junction eight onto the A20.
Kent Police said phase one of Operation Stack, between junctions 11 and 12 coastbound, was not in place as part of the current measure.
It said phase two had been implemented as it had proved to be "highly effective in keeping traffic moving" when it was used in February.
Motorists are being urged to plan their journeys in the run-up to the bank holiday weekend, to carry water and food in case of queues.
They are also advised to check with cross-channel ferry operators before setting off for scheduled sailings.
The Folkestone to Calais Eurotunnel shuttle service that carries freight and cars is running normally.