The revised budget, down to an upper limit of £1.4 billion from £1.45bn, was announced during a site visit this morning by deputy first minister Nicola Sturgeon.

The further reductions in the budget are the result of the continued delivery of key construction milestones, successful management of the project and prevailing market conditions. The project is due for completion by the end of 2016.

Ms Sturgeon said: “It is very positive news to be able to announce a further £50m worth of savings from Scotland’s biggest infrastructure project in a generation.

“We have already seen last year’s savings from the FRC (Forth Replacement Crossing) benefit other projects, allowing work to start early on the dualling of the A9 for example.

“The progress made since construction started in June 2011 means we have delivered £195m worth of savings. The sound management and delivery of the scheme should be warmly welcomed.

“Not only is the project delivering value for money, it is also benefitting the Scottish economy with subcontract and supply orders for Scottish companies and over 1,000 people currently directly employed on site.

“We recognise there are still challenges to overcome in the years ahead but it is very pleasing to report that with the first sections of deck being placed just last week, the project remains on schedule to be complete by the end of 2016.”