SCIENTISTS from Southern Water have been given top marks in a water safety audit carried out by a government watchdog.

The company, which supplies water to more than one million homes in the south-east, including Hampshire and the Isle of Wight, routinely tests for more than 100 substances to ensure the region's supplies are among the best in Europe.

One of the most important is cryptosporidium, a water-borne parasite which can cause stomach upsets. Southern Water's sampling programme enables the company to detect even the lowest levels of the bug, well below those which could affect health.

The Drinking Water Inspectorate audited Southern Water's cryptosporidium laboratory in Brighton and awarded the company's team top marks.

Barry Evans, scientific services manager, said: "The rules associated with the audit are very stringent so it was a real success for the company to be rated so highly.

"It is a reflection of the commitment and ability of the staff, and the importance Southern Water places on supplying drinking water of the highest quality to its customers in Sussex, Kent, Hampshire and the Isle of Wight."

Southern Water scientists carry out a minimum of 11 tests each day for cryptosporidium, which measures only five microns in diameter (one micron is a thousandth of a millimetre).

Each test takes a minimum of two hours and is carried out to forensic standards, with samples kept under lock and key from the point they are collected to the moment they are analysed.