WORK to electrify the railway into Oxford has been set back by four years, it was confirmed tonight.

Network Rail – the firm that manages Britain's rail infrastructure – says it is now aiming to finish electrification of tracks between Didcot and Oxford by 2019, with further electrification to Bletchley not expected to begin until 2020 at the earliest.

Electrification to Oxford was originally set to be finished next year.

Council leaders said it was "a big disappointment" that would leave passengers in Oxfordshire waiting longer for better services.

A spokesman for Network Rail told the Oxford Mail: "It is too early to give details about when the projects will be delivered, because we will have to sit down with all our partners in Oxfordshire and determine what the plan for Oxford now looks like."

Ian Hudspeth, leader of Oxfordshire County Council, added: "It is clearly important to make sure these schemes get delivered properly and sensibly and we need to work with Network Rail rather than against it.

"But I will be making sure it is aware of the disappointment of the residents of Oxfordshire about these delays.

"More reliable and efficient train services mean fewer people will use their cars and that means less congestion, which is really important for the county's plans."

The news emerged in a major review of Network Rail's projects carried out by chairman Sir Peter Hendy, who was parachuted in by the Government earlier this year to help rein-in massive overspends and lengthy delays.

The firm has prioritised the electrification of the Great Western Mainline between London Paddington and Cardiff, but said the section branching off to Oxford would be done later.

It said this was for "engineering reasons", such as heavy machinery already being stationed in other areas, work on signalling and tracks already taking place around Oxford and flood prevention works set to be carried out at Hinksey.

Engineers would still aim to complete electrification between Didcot and Oxford within "the back-end of control period 5" – which covers 2015 to 2019 – the firm's spokesman said.

It came after a damning report by the House of Commons Public Accounts Committee last week, which said Network Rail had "lost its grip" on managing major projects.

The firm's plans for electrification – which include the tracks between Oxford and Didcot – are reported to have risen in cost from £1.6bn to as much as £2.8bn in just one year.