It will be the first large-scale new water storage reservoir built in the UK since the 1980s.

The Future Water joint venture of civil engineering contractors Mackley and Jones Bros beat competition from Balfour Beatty and Hochtief to land the work.

The £41m pipeline installation element of the job was awarded last year to Ward & Burke Construction Limited.

Bob Taylor, Chief Executive Officer at Portsmouth Water, said: “This is a major milestone for the Havant Thicket Reservoir project, and we are delighted to have these two exceptional contractors delivering the scheme.

“We were highly impressed by the proposals put forward by Future Water MJJV and Ward & Burke during the tender process, with both companies being able to call upon vastly experienced teams, with strong track records in successfully delivering major infrastructure.”

Taylor added: “We look forward to working closely with both companies to progress and complete this environmentally led project on time and within budget.

This includes honouring our commitment to leave a really positive legacy by creating opportunities for local employment and skills development through the reservoir scheme.”

Future Water Director Ben Hamer said: “Future Water is delighted to have been selected by Portsmouth Water to deliver this critical piece of water infrastructure for the South East of England. As a regional company, legacy projects, such as this, are central to the values of our staff and stakeholders.”

Mr Hamer’s fellow director John Dielhof added: “It’s a project that we can’t wait to get started on because we know how much of a positive impact it will have on the region.

“The scheme will safeguard dozens of jobs for our skilled workforce, as well as create opportunities for apprentices and trainees to kickstart their civil engineering career with us. In addition, we are excited to see the impact this has on the local economy, through supply chain opportunities and spend in the local area.”

Once completed in 2029, the reservoir will hold approximately 8.7 billion litres of water and be able to supply up to 21 million litres of water each day.

It will be one mile from east to west, half a mile from north to south, with a new wetland on its northern shore, and is being built on a 160-hectare grassland site which has been owned by Portsmouth Water since the mid-1960s.

A new two-mile long pipeline, which is designed to be largely tunnelled, will also be built to fill Havant Thicket Reservoir in the winter with surplus water pumped from nearby Bedhampton Springs. It would also be used to draw water from the reservoir to supply customers when it’s needed.

The reservoir was granted formal planning permission in October 2021, with a further planning application for the new pipeline expected to be submitted in Summer 2023.