The firms will work for Scottish Water and its alliance partners Byzak/Black & Veatch over the 2015-2021 regulatory period.

Estimated spend with the selected civil engineering contractors will be around £25m each year in each of the three lots.

Between one and three firms will be selected for each specialism covering infrastructure, sewer rehabilitation  and electrical and mechanical works.

Expressions of Interest must be submitted to Scottish Water.

Scottish Water signed two alliance deals to cover its headline spending programmes. The first for a £340m spend on waste water infrastructure with BBV Alliance – Black and Veatch and Byzak (part of Amey).

It water infrastructure alliance is with Morrison Utility Services and Aecom and covers a projected £360m of spend over the six years.

Part of the work programme will be delivered by alliance partners with the remainder delivered by contractors.