Earlier this year, energy firm SSE Generation won more than £100m in compensation in a claim against contractor Hochtief who designed and built the underground passage at the Glendoe site near Fort Augustus between 2006 and 2008.
The £140m Glendoe plant was officially opened by the Queen in June 2009 but operations had to be suspended when there was a collapse of rocks inside the tunnel, which carries water to the facility from a reservoir.
Under the construction project a head race tunnel (HRT) ran more than six kilometres from a reservoir at Glen Tarff to the turbine before a shorter tunnel then discharged water into Loch Ness.
Operations did not resume until three years later.
Read: Blog: Glendoe Tunnel – the collapse of reasonable skill and care? – Rebecca Barrass from MacRoberts looks at the litigation surrounding the project
In 2016 a commercial judge at the Court of Session in Edinburgh ruled against SSE in the substantial part of its claim.
Lord Woolman said he was satisfied that Hochtief did exercise reasonable skill and care in the project and that the collapse was an “employer’s risk event” but awarded £1m to reflect the period when the scheme was out of action.
But after an appeal by Perth-based SSE to three judges they ruled in favour of the firm earlier this year by two to one in their legal challenge.
Hochtief has applied to appeal the case to the UK Supreme Court and Lord Carloway, sitting with Lord Menzies and Lord Glennie, have granted permission for the move.
Kenny Mcbrearty QC, for Hochtief, argued that the action raised matters which met the test of general public importance and that guidance was required from the Supreme Court.