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A21 Tonbridge to Pembury

The existing A21 route had been a major bottleneck on this major route to the South Coast for decades and the scheme had been in planning for a number of years. Even though the scheme was only 4km long, the site was at the higher end of road improvement challenges, due to multiple SSSI, ancient woodland, and archaeological and wildlife-sensitive sites throughout the route. On top of all this, the presence of Dormice and other protected species on site meant that an already tight program had to be shortened still further. Due to the importance of the project, Highways England had direct involvement throughout and had a permanent presence on-site to supervise the works.

Kingwell Holdings Ltd. (KHL) was called in by BB to work as principal contractor, taking charge of both the tree and vegetation clearance, as well as running the ancient woodland soils translocation sub-contractor Alaska Environmental Ltd. and as such, had a full complement of management, engineering and supervisory staff on site.


The de-vegetation works commenced at 9 hectares, but quickly grew to 13ha and soil translocation at 8ha, all within the existing program, meant that KHL had to deploy major resources on-site to meet the program deadlines. Powerpack excavator mulchers, tracked RT400 excavators, forestry excavators, slow-speed shredders, and numerous saw/climber and chipper gangs, worked flat-out to meet program milestones in all weathers. Operations ran around the clock, with 3 separate night crews at one point.

Challenges / Notes / Innovations

KHL operates a unique fleet of equipment that has been designed, developed and perfected over 3 decades of specialist work in the industry. This equipment was one of the reasons why all milestones and challenges were not only met but were completed well in advance of program deadlines. It was widely acknowledged by all stakeholders that only KHL could have completed this scheme, as no other specialist contractor possessed the skills, experience, and resources to successfully manage and complete the works of this complexity and scope.

Working with renowned mammal specialist Dr. Paul Channin, new methods of sensitive vegetation clearance in the Dormouse areas were developed and tried by KHL in close partnership with Dr. Channin, and these were approved by Natural England, to ensure that the increase in scope did not affect project deadlines.

As the only contractor in Europe to operate a fleet of mulching equipment of this size, multiple sites were successfully cleared, without having to bring in sub-contract resources.

Simultaneous management and integration of the soil translocation work and the de-vegetation works by KHL, enabled program deadlines to be shortened, where separated worksites would have caused unnecessary delays.

Innovative mechanised methods of clearance shortened program phases and enabled groundworks to commence early.

Large areas of bio-degradable haul routes across SSSI and ancient woodland were successfully created, using coarsely-shredded material, produced by KHL, using their tracked shredders.

The majority of timber from the ancient woodlands went to local sawmills for processing into quality timber.

This scheme was a prime example of how a specialist subcontractor can deliver on multiple levels, when allowed control of the works (within project program restrictions) and still maintain ecological, environmental and legal compliance with the various stakeholders.