MAYOR OF London Sadiq Khan has directed Transport for London not to take responsibility for any further cost increases for the Metropolitan Line extension from Croxley to Watford Junction.

The project, formerly known as the Croxley rail link, transferred from Hertfordshire County Council to Transport for London for delivery in November 2015, with TfL made responsible for any costs above the £284.4 million funding package. However, TfL now says the outturn cost of the project will be ‘significantly in excess of’ this amount, which weakens the business case. Combined with a loss of operating grant, TfL says this means it is no longer able to bear cost risk above the current funding package.

TfL says ‘an alternative source of additional funding’ will need to be identified to cover the cost increase if the scheme is to proceed.

The body says reimbursement of sunk project costs ‘is likely to feature in discussions between the funding partners and TfL’ should the scheme not proceed; TfL’s spending on the project is expected to total £71.2 million, including £15.5 million for an additional ‘S’ stock train.

The scheme involves extension of the Metropolitan Line from just north of Croxley, running on a new 400-metre viaduct over the Watford Road dual carriageway and the Grand Union Canal and onto the track bed of the former British Rail Croxley Green branch line to Watford High Street and Watford Junction.

New stations would be built at Cassiobridge and Watford Vicarage Road, and although the existing Watford LU station would be closed to passengers it would be retained as sidings for the extended railway.

The extension was initiated in 2011 as a Hertfordshire County Council scheme with a funding package of £116 million from HCC and the Department for Transport, at which point it was due to open in May 2016. However, it became subject to cost escalation and programme slippage, which led to TfL being appointed as delivery agent, providing up to £46.5 million of funding and being accountable for any further cost increases, with opening rescheduled for late 2020. At the point of transfer the estimated cost was £299 million, already in excess of the funding package, with a benefit-cost ratio of 0.4:1. A subsequent June 2017 estimate suggests the cost will be £333 million, with a further £24 million of cost pressures identified against this total, further weakening the BCR.