Tests on the bodies of dead ducks and swans found on the River Great Ouse in St Neots have determined that the birds were not poisoned.

This follows inconclusive post mortem examinations which found no signs of disease and an investigation which confirmed that the water was not polluted.

In total, 15 dead swans and seven ducks have been spotted on the river between Mill Lane, Little Paxton and St Neots Marina since sightings began.

A spokesman for Natural England said: “The tests were all negative, there were none of the usual suspects that we would expect to find if they had been poisoned.

“We will now go back to the police to pursue other lines of enquiry.”