Eight years ago Ealing Council wanted to redevelop a 45 acre (18.5 hectare) area of derelict parkland in Northolt, which had become an eyesore.
They recruited a firm of consultants, led by landscape architect Peter Fink, who came up with a solution which included the creation of four man-made hills on the south side of the carriageway.
Mr Fink realised that a number of huge civil engineering projects were about to get under way in West London, including the redevelopment of Wembley stadium and the Westfield shopping centre at White City, and knew the builders would need to get rid of large amounts spoil.
"We offered to take all this spoil at our site, charging between £70 and £90 per lorryload, which meant the developers only had to haul it 10 miles rather than 100 miles to a landfill site," says Mr Fink. He says this process reduced the overall "carbon footprint" of sites such as Wembley and White City.
Around 60,000 lorryloads of spoil and concrete was dumped on the site, which generated so much money the council actually made a profit out of Northala Fields. The spoil was used to create the four hills while the concrete was crushed and used in gabions – walls surrounded by steel cages, which provide a spiral path up the tallest hill.
So, build hills, make money.
Read the full story at the BBC.