Client Transport Scotland is delighted to cut at least £20m from the cost of improving Junction 1a near Kirkliston as part of the Forth Replacement Crossing project.
But stunned major rivals will point to another case of low-cost bidding as the construction market becomes increasingly competitive.
Sisk and Roadbridge beat three rivals to win the job – Morrisson Construction and joint ventures between Balfour Beatty and Morgan Sindall and Sir Robert McAlpine with Costain.
Cabinet Secretary for Infrastructure and Capital Investment Alex Neil said: “Today’s announcement that the preferred bid for the M9 Junction 1a contract is substantially under budget demonstrates further significant savings for the public purse.
“While it is clear that the current construction market is highly competitive, this is also testament to Transport Scotland’s robust procurement and project management.”