Dog walkers have been advised to keep their pets away from water at a popular beach.

Colchester Council said it had been alerted to a substance along the waterline at West Mersea.

In a tweet it said: "We are aware of a substance along the waterline at West Mersea Beach.

"It is currently unidentified, but the Environment Agency are aware and are carrying out tests.

"As a precaution, we recommend that dogs are kept on a lead and away from the waterline until further notice."

Readers also reporting seeing a substance on the beach at Clacton.

It is not yet known if it is the same substance.

A Tendring Council spokesman said: "We are aware of a substance in the sea off the coast between Clacton Pier and Holland-on-Sea.

"It is currently unidentified, but the Environment Agency is aware and carrying out tests

" As a precaution, we recommend dogs are kept on leads - on beaches where they are allowed - and away from the waterline until further notice."

A spokesman for the Environment Agency said: "“We received an initial report from a member of the public at 09.10 this morning reporting that an orange liquid was washing onto the beach at West Mersea, and that there was a lot of debris associated with this.

“It is in long strips along the beach and coming in on the incoming tide.

“It stretches for several hundred metres in either direction from Seaview Avenue.

“We have officers on site now assessing the incident and trying to identify the substance. We have also been liaising with Colchester Borough Council who would normally lead on any shoreline clean-up of public beaches, should it be required.

“We have since received similar reports from members of the public in Clacton and we are liaising with Tendring District Council at that location.

“Samples taken at West Mersea today will be analysed by our experts, working with CEFAS, with results due in 24 hours.

“No signs of any dead or destressed wildlife have been found and initial observations suggest this may be the result of a natural event.”