The stack is back

Published on 21 May 2018

Operation Stack - in which the M20 through Kent is progressively closed and used as a temporary lorry park during cross-channel travel disruption - was supposed to be temporary. In 2015, plans were announced to end it. But new plans announced this week suggest that, far from going away, it may become much more common.

Back in summer 2015, we published a new article all about Operation Stack. In that year it was deployed more than ever before, including one stint that covered the whole of July. It was just our luck that, as soon as we'd published an article explaining how few alternatives there were, the Government announced that the events of 2015 were not to be repeated and a permanent solution would be found that would mean an end to the Stack.

Elsewhere on

Operation Stack

If there's trouble crossing the Channel, you'll see the lorries queuing on the M20. What is Operation Stack? Why does it cause so much trouble? And why, more than twenty years after it started, are we still using it?


A range of alternatives were suggested. Highways England gamely investigated all sorts of possibilities, from the disused airport at Manston (too far away) to the Kent County Showground at Detling (whose owners were not very keen) to a range of miscellaneous plots of land adjacent to various motorway junctions (where the locals tended to kick up a stink). Money was pledged but there has not, yet, been found a location where the money can be spent. Operation Stack is still waiting in the wings.

An idea whose time has come?

Last week, the Department for Transport proudly announced some "new plans" to keep Kent moving in the event of "Channel disruption". The new plan is that, when Operation Stack is implemented on the coastbound carriageway of the M20 between junctions 8 and 9, the Londonbound carriageway will operate in contraflow. Other traffic can then remain on the motorway instead of being diverted off to use the A20. That section is normally used for phase 2 of Operation Stack - it's not yet clear whether it would become the first phase in future.

Highways England has been tasked with making this possible from early 2019, and they have gamely agreed. Before it can happen they will need to carry out some fairly extensive work to strengthen the hard shoulder of the Londonbound carriageway so that it can withstand use as a running lane over extended periods of time. Most motorways have shallower foundation layers beneath the hard shoulder because it was never expected to be used as intensively as the main part of the carriageway - this is why many Smart Motorway schemes include significant work to strip out and rebuild the hard shoulder right down to the road's sub-base.

The other factor that explains why this can't happen sooner is that a way needs to be found to reliably operate thirteen miles of motorway in contraflow at a moment's notice. That requires a huge quantity of traffic management equipment - cones, barriers, signs and so on - which must be nearby and not already in use. It requires a number of people with the necessary vehicles and skills to be able to safely and competently set it out. And it requires time.

Therein lies the problem: the contraflow has been attempted twice before and the (then) Highways Agency gave up on it both times.

The Concrete Moveable Barrier in action on the M20 - a rare sight even when it was there. Click to enlarge
The Concrete Moveable Barrier in action on the M20 - a rare sight even when it was there. Click to enlarge

In 2008, a concrete moveable barrier was installed on the Londonbound carriageway between junctions 11a and 12, with a special vehicle deployed to shift it into the middle of the road to form a contraflow when required. The equipment and vehicle were on lease, but were only used twice in four years - at an estimated total cost of £13m. The system was removed in 2012.

A trial was also conducted where a more conventional contraflow was installed. The results of this experiment were not encouraging - the cost of hiring the traffic management equipment was significant, and the time it took to deploy was disappointingly long.

Then, in 2015, during the longest period that Operation Stack has been deployed, while the rural roads of Kent were struggling to cope with a month-long closure of a major motorway, Highways England declared that a contraflow would be an "unacceptable risk". And that aside, setting up thirteen miles of contraflow is a job that would take so long that it would take several days to set out - by which time the Operation might be called off.

So, whatever contraflow solution Highways England come up with must be safer than what they had in mind three years ago, it must involve equipment reserved for this task and stored nearby, it must involve a staffing plan that will work at the drop of a hat, and it must be capable of being set out and cleared away with astonishing speed. No small task.

Why now?

Operation Stack hasn't been called upon for a little while, and the last we heard, the Government was supposedly fixing up a proper, permanent alternative to it. Something must have changed to cause this announcement.

An empty M20. Don't get used to it. Click to enlarge
An empty M20. Don't get used to it. Click to enlarge

There seem to be two factors, and the first has been gradually permeating every aspect of government policy for the last two years: Brexit. In March 2019, the UK will leave the European Union, but it's not (at the time of writing) even remotely clear what our new relationship with the EU will look like or, more importantly for the M20, how the border points at Dover and Folkestone will operate. It is not a coincidence that these measures will be ready in time for "early 2019". They form part of the contingency plan in case the border does not work as smoothly and quickly as it does now, because any additional time spent on customs formalities risks a long queue of lorries, and a long queue of lorries means Operation Stack.

The second factor is that there is still no alternative lorry parking facility for use when the channel crossings are disrupted. Reading between the lines, the Department for Transport's hopes of finding a permanent solution that will mean Operation Stack can be retired seem to be fading, because they are now spending money on making Operation Stack work more effectively and with fewer unpalatable side-effects. That's not something they would be doing if they were making steady progress on a plan that would make it redundant.

In fact, far from being on the way out, Operation Stack shows every sign of digging its heels in and being with us for much longer than anyone would hope.


The obvious solution is a third, parallel carriageway coast bound. But that's far too expensive and nimby.

Floyd Pitt 24 May 2018

Ask the Japanese. They'd have an efficient system. Although a train did leave 25 seconds early at a Japanese station last week, which caused a bit of embarrassment- and no doubt someone lost their job over it- so standards are slipping even there, it seems.

Damian 24 May 2018

Or another obvious solution is use the M26, as it has a natural motorway diversion.

Steve 24 May 2018

Thinking about this now in 2018 with the Smart Motorway program expanding rapidly, the signage part of the operation could all (or significantly) be achieved electronically using the same gantries and variable signs etc currently being deployed on all the Smart Motorways. These would not be used under normal running, only when needed at short notice for the contraflow. That then just leaves the minor issue of rapidly installing 13 miles of temporary concrete barrier without advanced warning...

Is there an equivalent operation on the French side of the Channel? Or is it less needed because there are three motorway approaches to Calais rather than one (A16 from the south, A26 from the southeast and A16 from Belgium)?

Usually, the hard shoulder of the A216 (a spur motorway linking the A16 and A26 intersections to the port of Calais) is used for this purpose for the port and the A16 for the Channel Tunnel.

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Picture credits

  • Photograph of Concrete Moveable Barrier: Kent Online.

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Published21 May 2018

Last updated4 February 2020