Professor Rory Mortimore has teamed up with South East Water to study the chalk formations of the South Downs as it lays a 3.7km (2.3 mile) pipeline through its core.

Working alongside contractors, he is able to research geological mysteries by extracting chalk samples from the 1.5 metre deep trench, which runs from Poverty Bottom, near Bishopstone, to the top of the downs at Firle.

The samples will help him to study geological formations between 70 million and 90 million years old, back as far as the last Ice Age, which could determine how the downs were formed.

He said: 'Having a long linear pipeline running through the South Downs has given us a unique opportunity to glimpse into our geological past and expand our knowledge.

'We've effectively crossed through 20 million years worth of time by being able to study the chalk formations of the South Downs, at depth, which is giving us more accurate data in terms of why certain things have occurred, such as the style of fracturing in the rock.

'We have even found layers of rock that were unexpected, having been formed during the last Ice Age.

'We frequently have construction activities across the region and we simply lose the opportunity to record the geology and dig deep into our earth's history to learn more about its makeup.

'Working with South East Water has given us a fantastic opportunity to do just that, so we can then improve and update our records and maps as part of the national database.'

Trevor Muten, from South East Water, said: 'The chalk of the South Downs forms a strategic part of our water supplies.

'Nature has effectively given us superb, natural underground water stores, called aquifers, from which we supply water to our customers.

'However, as with any natural environment we take water from, we need to ensure it has a sustainable future.

'That's why we're delighted to be working with Professor Mortimore as his expertise and knowledge will help us better understand how the chalk block functions and how it interacts with the wider water environment.'

South East Water's £1.25 million pipeline scheme, to be completed by next month, will transfer water from Poverty Bottom Pumping Station near Bishopstone to Firle Service Reservoir, on the top of the South Downs near Firle Beacon.

From there it will flow by gravity via existing underground water mains to Ringmer and then Burgess Hill.