Updated: Construction News has learned that a £600m contract to build the Northern line extension to Battersea has been delayed by several months, but all four shortlisted bidders remain in the running for the scheme.
According to documents presented at a Transport for London board meeting, the project has been held up due to objections to the Transport Work Acts Order which will authorise the construction of the work.
Prequalification questionnaires were submitted by six consortia before TfL shortlisted four bidders in June, understood to be a Bam Nuttall/Balfour Beatty joint venture, Bechtel/Strabag, Costain/Sir Robert McAlpine and Laing O’Rourke/Ferrovial.
TfL confirmed to Construction News that all four bids remain on the table despite the delay, and that a total of £1,985,150 has been set aside for design costs in the 2013/14 financial year.
The main design-and-build invitation to tender document was due to be issued in September, but will now be issued next month instead.
Tenders are due to be returned in February rather than January 2014, with a contract award due to follow in the summer rather than spring of that year.
The TWAO is now expected to be granted in autumn next year, but the contract award will contain a break clause to enable TfL to cancel the deal before main construction begins.
Latest estimated costs for the overall scheme total £1.04bn, which has been reduced from the £1.17bn forecast in Q1 this year.
TfL said this had been achieved due to incorporating value-engineering initiatives, such as the removal of temporary shafts south of Kennington and a “reassessment of the internal resources required to deliver the programme”.
Asked by Construction News whether the reduction in overall cost had reduced the construction cost, TfL declined to comment.
A spokeswoman said: “At this stage we cannot give a full breakdown of the final estimated cost for the scheme as this would interfere with any future commercial tender processes. We expect that early contractor involvement would help to reduce final costs, as has been successfully proved with the recent Bank/Monument Tube station redevelopment.”
The transport body will commence design, site surveys and early enabling works ahead of powers to commence construction being granted.
A public inquiry will begin next week into the scheme, which will see around 3.3 km of new tunnels built, including over-run tunnels and ventilation shafts, as well as new stations at Nine Elms and Battersea.
The scheme will be benchmarked against recent major procurement schemes such as Crossrail and the £500m Bank Station Capacity Upgrade programme, awarded to Dragados in July.