The significant problems encountered by Highways England and their contractors were:- - the removal and treatment of a previously unidentified old contaminated landfill site which was buried in woodland and unknown at the tender stage, - the need to excavate old concrete/tarmac within the central grassed reservation which was not identified by site surveys at the tender stage, - the need for an additional infiltration pond, - a change to the central pier design which while increasing short term costs will save long term maintenance costs. Discussions with the contractors are ongoing. Highways England does not hold lists of contractors but is able to take into account past performance as part of their procurement process.