This contract was let to Arthur Monk and Co Ltd. at the end of December 1969 for the tender sum of £7,196,155. The length was 12.2 miles and the tender period was 24 months. The works were located entirely in chalk and required approximately 3,250,000 cu.yds of excavation and over 200,000 cu.yds of imported material. The work was situated high in the Wiltshire and Berkshire downs and included the interchange with the A388 and the Membury Service Area. Monks were an experienced Motorway Contractor, having carried out a number of Motorway projects and their Director, R, Whittle was well known in the Industry as a very knowledgeable contractor. Their Project Manager, Reg Castell, also was well known and had come originally from a structures back ground, having worked for a number of contractors including Tarmac Civil Engineering (now Carrilion Construction) on M5 in Worcestershire.

Chalk country is characterized by swallow holes in the strata and this length of Motorway had examples which had to be dealt with. At one bridge site excavations for the foundations exposed a vast cavity which it was decided was a chalk mine and which had to be remedied with large quantities of concrete. No other information of note has been obtained about the difficulties or the success of this section.

A more detailed description of the section of the M4 between Holyport (Junction 8/9) and Tormarton (Junction 18), summarised from the opening brochure, can be accessed by clicking here.