Toilets come in many shapes and sizes around the world: squat and throne, dry and flush, indoor and outdoor. Most of us use one every day, but over two billion people still do not have access to facilities, leading to health and sanitary problems and even risks for personal security.

From the 50 seater public toilets of ancient Rome and the modern flush toilet, invented by a godson of a 16th century British monarch, this feat of human engineering is believed to date back 5000 years to the Indus Valley Civilisation. In recent years it’s become a battleground for equality, but in a world of increasing water shortages, could the flush toilet become a thing of the past?

Joining Bridget Kendall to discuss the history of the toilet are Ann Koloski-Ostrow - an archaeologist specialising in Roman toilets from Brandeis University in the United States; Barbara Penner - a Professor of Architectural Humanities from University College London and the author of books on public toilets and the modern bathroom; and Dr Bindeswar Pathak - a sociologist, social activist, and Founder of the Sulabh Sanitation and Social Reform Movement. He is also the inventor of an environmentally friendly compost toilet that’s used widely around India today.

Photo: A close-up of a toilet (Getty Images)