Happy World Toilet Day! It is that day of the year when we all need to overcome our embarrassment and discuss what is normally a taboo topic. Hundreds of millions of people still have no access to a toilet, putting them at risk of disease, sexual assault and public humiliation.

Tamasin Ford speaks to the inventor of World Toilet Day, Jack Sim, about how much has been achieved since he founded his World Toilet Organisation 20 years ago to promote discussion of this topic. We also hear from Catarina de Albuquerque, who served as the first United Nations Special Rapporteur on the right to safe drinking water and sanitation, and made it one of the UN's sustainable development goals.

Also, consultant Timeyin Uwejamomere talks about the challenge of introducing proper sanitation in the slums of his native Nigeria. Plus Chilufya Chileshe, policy director at the charity WaterAid, explains how the lack of a toilet leaves women and girls vulnerable to sexual harassment, and interferes with their education.

(Photo: An eco-friendly mobile toilet in Johannesburg, South Africa. Credit: Deon Raath/Galo Images/Rapport)