A state-of-the-art laboratory is testing the quality of drinking water for 2.2 million people 24 hours a day, every day of the year.

The facility in Farnborough, Hampshire, is operated by South East Water and tests 500 samples a day for 200 different substances to ensure drinking water is clean.

Managers at the laboratory say climate change and measuring microplastics are among the issues they have to consider as future risks.