M20 traffic with Operation Brock in force.

What is Operation Brock? M20 traffic and Channel Crossing guide

Consumer Editor

3 minute read|22nd Oct 2025

If you are looking to take a car journey to Europe, it is important to be aware of what to expect on your journey. This is why it is vital to know everything about Operation Brock.

As families pack their cars for a road trip, worrying about being stuck in hours of traffic is probably not at the forefront of their minds.

However, the main routes to the English Channel crossing can sometimes be backed up for miles.

The guide will provide the driving advice you need for your next journey to France and continental Europe.

What is Operation Brock?

Operation Brock refers to a traffic management system that was initially planned to be implemented in the UK in response to potential disruptions caused by the country's withdrawal from the European Union.

However, despite the impact of Brexit, the operation remains an option for the Government, as it was specifically designed to manage traffic flow in the event of congestion or delays at the Channel ports, such as Dover, which are major gateways for trade and holiday makers between the UK and the European mainland.

When in use, it is put into operation on the M20 motorway in Kent.

It is a contraflow system on certain stretch of the motorway where one lane is used for both directions of traffic. This system allows for greater flexibility in managing traffic during periods of heavy traffic or disruption.

One of the other key facets of Operation Brock is the use of ‘Lorry car parks’. This is where a convoy of lorries can be temporarily held to alleviate congestion.

Impact of Operation Stack

Prior to the introduction of Operation Brock in the wake of Brexit, there was a similar system in place.

It was also used during times of traffic disruption, congestion, or industrial action at the English Channel ports for both lorries carrying goods, and for those looking to take a holiday to Europe.

Parts of the M20 were divided into ‘stacks’, where each with specific areas allocated for different types of vehicles.

Facts about M20

Operation Brock is based on the M20 motorway in Kent. It is the main stretch of road that connects London to Folkestone, and travel options into mainland Europe.

The 50-mile stretch of motorway starts from the Swanley Interchange in Kent and ends at the junction with the A20 near Folkestone. A lot of the road uses smart motorway technology.

However, the motorway intersects with the M25 motorway near Swanley, which provides drivers a link to London.

At Ashford, the motorway connects to the A20, which then leads to the Channel Tunnel and the port of Dover.