A stream in Huntingdon which baffled residents by constantly changing colour has been polluted again - this time by oil being dumped in the water.

Investigations are now taking place to try to trace the source of the oil which has led to the stream, which runs through the Riverside Park into the River Great Ouse near Hartford, being fenced off and absorbent pads being used to remove the pollution.

Last autumn the stream hit the headlines after park users noticed that it had started to run in bright colours, including blue and green.

The pollution was eventually traced to a business in the town's industrial area.

Some dog walkers also complained that their pets had become ill after going into the water.

Appeals have now been made for anyone with information about how the oil came to be in the water to come forward.

An Environment Agency spokesman said: "We were alerted to reports of pollution on Tuesday in the river that runs through Riverside Park in Huntingdon.

"Our officers attended the incident and deployed oil absorbent booms and pads to contain what looked like engine oil that had been dumped in the river."

The spokesman said: "Anglian Water sent out technicians to check their surface water drainage network as a potential source and confirmed that the oil pollution had not been discharged from their sewers.

"The incident is now in the hands of the landowner, Huntingdonshire District Council, who will be contracting an oil spill contractor to clean-up any remaining oil."

Neil Sloper, district council head of operations, said: "The Environment Agency alerted us of the oil pollution at Riverside Park, Huntingdon on April 17 and we appointed an emergency contractor to decontaminate the area and submit a spill assessment report to hopefully identify the origin of the oil.

"We thank the Environment Agency for their support in this incident and our operations and community safety teams are now working together to investigate the matter.

"If anyone witnessed the fly tipping taking place in the area on Tuesday we urge them to contact the Environment Agency incident hotline on 0800 80 70 60 or the Huntingdonshire District Council Call Centre on 01480 388640. Please be aware that engine oil can be recycled at local household recycling centres."