The framework will be awarded for an initial six-year term, with a facility to extend the agreement in one year increments up to a maximum of four years.

Services will be split over three streams covering core water, waste water renewal and repair work and non-core work for smaller projects and specialist works.

Shortlisted firms will be invited to tender on 19 July, with around four bidders expected to be pitched against each other for the main lots in streams one and two.

This morning Steve Mogford, chief executive, said the water company was on track to submit its PR19 business plan in September 2018.

United Utilities has pumped more than £817m of investment into the pipes, reservoirs and treatment works which deliver water and wastewater services to the North West’s seven million people.

The money – revealed in its annual results today – represents just 12 months of work in the firm’s record-breaking five year investment programme totalling £3.8bn.

He added that the group has met leakage targets for 10 consecutive years, and has cut leakage by half since the 1990s.

Reducing leaks remained a top priority and the use of satellite imagery to detect leaks, and in-pipe assessment techniques are being explored.

United Utilities is also the first water company to train a sniffer dog to specifically help pinpoint problem pipes in rural areas where the water does not always show on the surface.

‘Snipe’ – the UK’s first leakage sniffer dog.