A report by the National Audit Office has found that last year's decision to cancel several major electrification projects in the UK was driven largely by cost, without taking other factors into consideration. NAO sought to investigate why and how the government had cancelled the planned 25 kV 50 Hz electrification of the Cardiff-Swansea section of the Great Western Main Line, the Midland Main Line from Kettering to Nottingham and Sheffield and the Oxenholme-Windermere branch in the north-west. It concluded that the major reason was affordability. Cost increases had made Network Rail's investment plans for Control Period 5 (2014-19) undeliverable within the available budget. DfT calculated that cancelling the three schemes would save a maximum of £105M in CP5 and avoid a further £1.385bn of spending in CP6 (2019-24). Secretary of State for Transport Chris Grayling had claimed that electro-diesel trainsets would be able to provide many of the passenger benefits of electrification, with less disruption for engineering work. NAO concluded that it was too early to determine whether it would be possible to deliver the promised benefits without electrification.
Railway Gazette, May 2018. p.26.