The redevelopment of Queen Street Station is already facing major delays after MSPs were told that “a significant risk” had been identified.

The man in charge of the country’s rail services told a Holyrood committee it would be several more months before he could tell them how long the hold-ups to the overhaul of Glasgow’s Queen Street Station would last.

It comes amid major concerns raised about the planned one month’s free travel for monthly and annual season ticket holders, announced recently by the Scottish Government.

ScotRail chief Phil Verster said the operator had yet to agree to provide £1.8million of the £3m cost of the scheme, the contribution coming from the Service Quality Incentive Regime (Squire), a rail improvement fund generated by fines paid by the train operator for failing quality checks.

He also told Parliament’s Rural Economy and Connectivity Committee that work on Queen Street had been due to start in December but it would be a further three months before he could commit to a date.

Work is expected to begin during the second quarter of 2017, meaning it could be a full seven months behind if it does not start until June.

The redevelopment will replace the current 1960s main entrance at George Square, Millennium Hotel’s 1970s extension above the station 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.

A report on the administrative and contractual end of the redevelopment has been cited as the reason for the delay. It had been due to be forwarded to the country’s transport minister in July but will not be on his desk now until February.

Mr Verster told MSPs: “There is a significant risk which we have not been able to size currently which will be resolved in the coming months.”

A Transport Scotland spokesman said: “The redevelopment of Queen Street Station continues to make progress, some advance works are already under way and Transport Scotland authorised a further package of enabling works in December.”