Repair works on the Queensferry Crossing will continue until autumn 2019 - two years after the bridge was officially opened.
Snagging works were due to be completed by September this year - but Transport Scotland Michelle Rennie has now provided MSPs with a new timetable showing that some repairs have a target for this new date.
Areas needing attended to include drainage, wind barrrier, road lighting and mechanical work on the roaddeck.
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Transport secretary Micahel Matheson said he was “disappointed” by the news.
A spokesman for the Scottish Government’s Transport Scotland agency, which is in charge of the project, said: “Traffic management will come off in December, then return in spring to summer at night for the works.”
Work which won’t be finished until next year includes work inside the deck and on gantries, external and internal painting, and cable maintenance access cradles.
Neil Greig, of motoring group IAM RoadSmart, said: “Queensferry Crossing users will be rightly frustrated that work continues due to the contractors inability to get the right resources in place.
“They are the experts and they should have been able to predict exactly what was needed and when to try and get more things done before the winter season.
“Transport Scotland should be seeking cast iron guarantees that the new timescale will be adhered to.”
Mr Matheson said: “Our contractor, FCBC, have indicated they have not made the progress with the snagging and finishing works as originally planned.
“The target date for completing this work was September 2018 but they have informed us they require further time.
“FCBC have said they have experienced difficulty in mobilising the resources required to complete the outstanding works on the project.
“But they are confident they will finish all but two areas of the remaining works by December 2018, with work on the remaining two areas to commence in spring 2019.
“Where possible, traffic management will only be implemented during the night, as is standard across the trunk road network.
“In response to feedback from road users about night time traffic management during the summer months, additional processes have been implemented to ensure that traffic volumes are reduced prior to traffic management being installed on the bridge.”
A version of this story orginally appeared on our sister title, The Scotsman.