Operation stack has been under continuous review since first introduced in 1987. Similar schemes are in existence for other major ports.
A coned contraflow system has been trialled on the 10.5 miles (16.9 km) section between Ashford and Maidstone, to relieve the pressure on the A20, but it was costly and slow to arrange, taking two days to set up and two days to remove. Highways England have announced a plan to use quick movable barriers to set up a contraflow so that two lanes can be maintained.
Use of Manston Airport
Use of part of the car park at Ebbsfleet International railway station to temporarily park/queue up to 1,000 lorries
In July 2016 the Department for Transport announced that a new lorry park for 3,600 vehicles was to be built to the north of junction 11 of the M20, with new access from the eastbound motorway between junctions 10 and 11 at Stanford West, with completion expected by Summer 2017. However, in November 2017 the Department announced that "environmental obligations" had delayed this option and, instead, a linear lorry park along the centre of the M20, separated by traffic barriers, was under consideration.
No mention of brexit in any of these considerations. To date French industrial action has created the biggest headache and displayed the inadequacy of the existing scheme, hence the search for better alternatives.
Similar schemes operate at Stranraer and Felixstowe. Surprisingly Immingham, the UK biggest port, appears to have no emergency parking scheme publicised.