An ageing seafront leisure centre was evacuated when gas leaked through a filter - a week after the system was given a clean bill of health.

More than 100 people, including a class of schoolchildren and members of a disabled swimming club, were led from the King Alfred Leisure Centre in Hove after fumes built up eight times above safety limits.

About 80 pupils, parents and teachers from Westdene School in Patcham, Brighton, were taken to the nearby Princes Marine Hotel to be checked by paramedics after alarms alerted lifeguards to the leak.

They were joined by 30 members of the Dolphins disabled swimming group who were in an adjoining pool.

An investigation was under way yesterday to find out why the system failed so soon after it passed a safety inspection.

A spokeswoman for Brighton and Hove City Council, which runs the centre, said the alarm was raised when a fault in the filtration system was detected during a routine inspection.

She said: "A piece of monitoring equipment showed signs of a leak. The system had been inspected only a week ago and given a clean bill of health.

"Our officers will return today to inspect it again."

Sheeting was laid down for the swimmers, who were clad in silver space sheets, to walk on because they had to leave their clothes and shoes behind.

The alert was sparked after ozone, used to clean water in the pool, leaked from machinery in a plantroom. Ozone can cause breathing difficulties if inhaled.

Centre manager Kerry Taylor alerted emergency services and lifeguards ordered everyone out. They were eventually evacuated to the Princes Marine Hotel.

They included Westdene pupils Elliot Isted, six, Adam Pugh, six, Savannah Elliott, seven, and Jack Meares, six.

Savannah said: "I was a little bit worried when they said we had to leave."

Janet Stuart, 68, was helping husband Patrick, who has Parkinson's disease, during his first session with the Dolphins. She said: "I was worried as my husband needs medication with him all the time. We had to go to a chemist in the end."