A MASSIVE £230million project that will guarantee the water supply for people living in Wiltshire, Dorset and Somerset for the next 25 years is reaching a crucial stage.

Wessex Water is currently spending £1million a week on one of the most ambitious construction schemes ever undertaken by any water company in Britain.

The eight-year project is now half-way through and involves 50 schemes across the three counties that will ensure a secure supply of drinking water.

It will also allow Wessex Water to be able to move water from areas of surplus to areas of deficit during periods of drought or a supply crisis, such as mechanical failure or contamination.

The Water Supply Grid Project involves 150 miles of new pipelines being laid, 12 huge water storage tanks constructed and a series of 24 pumping stations being built or refurbished. The scheme is now heading towards Salisbury and the planned work involves the construction of a new two million litre covered reservoir – which has the storage capacity that is the same size of an Olympic-sized swimming pool.

The new reservoir, to be built at Camp Hill near the existing reservoir in Codford, will allow water to be supplied to Salisbury.

A new 75km (60-mile) transfer main pipeline will link another new pumping station at Sturminster Marshall in Dorset to the new storage tank.

Archaeological surveys are under way with the main construction works - including the new pipeline to Salisbury - set to start next month and run for a year.