THE body in charge of the UK's railways has said it cannot give a date for when the delayed redevelopment of one of Scotland's busiest stations will be completed.

Network Rail has told MSPs that the major contractual and legal wranglings holding up the overhaul of Glasgow's Queen Street station are ongoing, pushing the timetable back indefinitely.

Work, originally expected to begin in late 2016, had been rescheduled to the second quarter of 2017. But the required Government authorisations, knows as TAWS orders, are currently eight months delayed.

It is understood a key factor has been objections to the scheme from parties affected by it.

The Herald revealed the lag in the £120million scheme in January and again last month amid concerns for the impact on the redevelopment of the neighbouring Buchanan Galleries shopping centre.

In its letter to MSPs on Holyrood's Rural Economy and Connectivity Committee, Network Rail said: "At the time of writing there is no confirmed date for finalisation of the TAWS Order, or for formal decision by the Scottish Ministers.

"As we advised Transport Scotland on 8th November 2016, the impact upon overall completion date will depend upon the date at which the TAWS Order is granted, the terms of the Order and implementation of the order.

"The TAWS programme has taken longer than originally estimated by Network Rail. This is always a risk with such a statutory powers application and it is one of the reasons why this is a Transport Scotland retained risk. "

Network Rail, which is carrying out the Queen Street work for Transport Scotland, added that a 'programme review' was also ongoing "to consider delivery of the project and to examine what are opportunities are available to reduce the impact of the continuing delay".

The letter concludes: "We cannot provide a revised programme for the redevelopment of Glasgow Queen Street, until the programme review is concluded, and we have received a positive decision on the TAWS Order application and have considered the impact of any conditions which may be attached to the TAWS Order."

The redevelopment will replace the current 1960s main entrance at George Square, Millennium Hotel’s 1970s extension above the station, Scotland's third busiest, and Consort House will be demolished, and the canopy over the footway on Dundas Street will be removed.

The station platforms will be expanded to accommodate eight-car trains, and the overhead line on the high-level platforms of the station will be electrified. The waiting areas, entrances, and catering and retail spaces will also be extended, and new lighting and public address systems will be installed.

One source recently told The herald that due to the knock-on to the Buchanan Galleries scheme there is unlikely to be any major retail offering within the completed Queen Street for several further years, adding: “Queen Street will probably be a big empty glass box until about 2025.”

Scottish Labour transport spokesman Neil Bibby, referring also to the delays impact9ng on the new Forth Road Bridge, said: “Both projects will make a huge difference to the travelling public, and will become an important part of Scotland’s infrastructure.

“We need the SNP government to get on with the job of governing, which involves improving our transport network, rather than obsessing about independence.”