Popular St George's Bay in Birzebbuga has been closed for swimming because of a sewage overflow caused by someone who dumped a baby's nappy wrapped in a towel into the sewerage system, the Environmental Health Directorate said.

It said that investigations by the Water Services Corporation indicated that the incident may have been deliberate, with a manhole having been opened for the purpose.

"This irresponsible, premeditated act not only disrupted services but also caused a drainage blockage, which in turn resulted in the beach being flooded," the directorate said.

The WSC has filed a police report, and the authorities are currently reviewing CCTV footage from the area.

Seawater samples are being tested and the beach is being cleaned.