Four more seals have been found dead off the north Norfolk coast taking the death toll to 45 and prompting a renewed appeal for information to assist a year-long investigation.

The Marine Management Organisation (MMO), which took lead of the investigation from Norfolk Police in August, announced today that four dead seals were discovered in December.

Three of them have similar corkscrew type injuries, with a single, smooth-edged cut that starts at the head and spirals around the body, to the other seal carcasses found and the fourth is still being investigated.

All of the seals were found in an eight-mile stretch, between Wells, Morston and Blakeney.

It is feared that more seals than the 45 accounted for may be dead but have not been found.

The MMO, which regulates the use of English seas, wants anyone with information to come forward.

All information given will remain confidential and callers can remain anonymous, if requested.

Neil Wellum, head of Marine Conservation and Enforcement at the MMO, said: 'We are keeping an open mind on all possible causes as we collect information from as many sources as possible.

'We would welcome any information from residents around this area of coastline as part of our ongoing investigation.'

At present there is no evidence of any criminal activity and the cause of the seal deaths is yet to be established.

With support from the Norfolk Police, the MMO will continue work to determine the cause in an effort to eliminate risks to the local seal population.

The MMO continues to work with a number of key organisations and experts such as the Sea Mammal Research Unit, Natural England, the Eastern Sea Fisheries Joint Committee and others during the course of the investigation.

Anyone with information regarding these incidents, or their possible cause, should contact the MMO's Marine Conservation and Enforcement Team in Newcastle on 0191 376 2512.