The Mersey and its people – for hundreds of years it has been impossible to say which influences the other most. Without the river there would have been no port, no merchants, no ferries, no shipbuilding. Many of the towns and cities that were the cradle of the industrial revolution wouldn’t exist, and countless lives defined by their relationship to the water would have been lived differently. But the river, too, has been shaped by its people. Dredged, bridged and canalised, its natural flow has been changed to better serve us. It has been polluted by industry, and revived by a clean-up campaign that is the envy of the world. With the Mersey in the midst of a renaissance, many 21st century lives are still entwined with it, whether for employment, recreation or inspiration. From ferrymen to cabinet ministers, policement to anglers, their stories tell the tale of the Mersey, the river that changed the world. For more information visit: http://www.riverthatchangedtheworld.com/mersey In this episode, Diane Walker, an Environment Agency regulator talks about her work, the problems of tracing pollution in the Mersey and its tributaries.