INVESTIGATIONS were continuing today to try to find the source of an oil slick which damaged the county's coastline.It is thought the slick, which has affected hundreds of seabirds, was caused by a vessel washing out tanks at sea.

INVESTIGATIONS were continuing today to try to find the source of an oil slick which damaged the county's coastline.

It is thought the slick, which has affected hundreds of seabirds, was caused by a vessel washing out tanks at sea.

The stretch of coast between Aldeburgh and Lowestoft was at the centre of emergency operations yesterday as conservation officials tried to rescue birds which were still alive.

But it is thought the natural action of the wind and waves have sunk the source of the contamination – an oil slick one mile long and 10 metres wide – to the bed of the North Sea.

Twenty-four hours earlier the slick had been seen on the surface of the sea seven miles off Southwold and other parts of the Suffolk Heritage Coast.

There is still a risk a large amount of oil will come ashore – contaminating "blue flag" beaches and wildlife habitat – and officials will wait until this morning to see what clean-up operations will be necessary.

Contaminated sea birds still alive, including guillemots, great crested grebes and red throated divers, were taken yesterday to the RSPCA hospital at East Winch in Norfolk, where efforts will be made to clean off the oil and restore the creatures to health.

The oil slick has been blamed on the illegal washing out of the hold of a tanker at sea.

Reports of dead and oiled seabirds came from all along the Essex and Suffolk coast, including from Lowestoft's south beach to the edge of the internationally-important Minsmere bird reserve.