A water company is using floating drones to survey the sewers under Milton Keynes.
Anglian Water is using the state-of-the-art technology to access more than 2.5 miles (4km) of the main trunk sewers that take used water from homes to the Cotton Valley water recycling centre.
The drone unit is floated down the pipes and uses laser, sonar and high definition CCTV to scan the pipes as it goes.
It builds 3D models of the sewers and reports the condition and silt build up in the pipes.