The various sections between Swanley and Maidstone and between Ashford and Folkestone went ahead in stages between 1973 and 1981. A number of problems arose, for example the need, due to ground conditions, to adopt side slopes flatter than the norm and the decision therefore to make them flat enough to be farmed right up to the motorway fence which was then located immediately behind the hard shoulder. There were also problems with unforeseen ground conditions on the West Kingsdown to Addington section and difficulty in agreeing a Final Account for a contract which had taken twice the contract period to achieve as well as the usual difficult decisions with landowners and sympathy with some of those affected.
Perhaps one of the more extraordinary events was the decision by Ministers, following a review of the road programme in 1980 or thereabouts, to suspend work on the section of the motorway between the eastern end of the Maidstone By-pass and Ashford. It was restored to the programme in the mid 1980’s after a period of heavy lobbying. The Engineer to the scheme was W S Atkins & Partners. The contract was let to Costains in January 1989 and the road opened to traffic in May 1991. The missing link in the motorway had the effect of deterring traffic, with drivers preferring to use A2/M2 to Dover: and this in turn meant that for many years the dual 3-lane motorway between Ashford and Folkestone was one road in England where you probably didn’t need to look both ways before crossing! When the motorway was finally opened all the way from Swanley to Folkestone the expected 80/20 traffic split between it and A2/M2 did not, it is understood, materialise but is nearer to 50/50. We shall never know to what extent this arises from drivers having become accustomed to using the latter when the link was not there.
The section of A20 between Folkestone and Dover is a dual 2-lane all purpose trunk road which continues seamlessly from the end of M20. It was interesting and unusual in that part of the scheme was included in the Parliamentary Bill for the Channel Tunnel. This was done partly to satisfy the Dover Harbour Board that the road beyond the Tunnel terminal was being taken seriously and partly to avoid potential problems of interaction between the two projects: at first the idea was to include the whole length to Dover in the Bill, but this would have been difficult to justify and was dropped. The section from Court Wood to Dover was taken forward through the normal highway procedures.