Oxford Canal bosses have promised to clean up a foul-smelling pollution slick which has been left to fester for more than two weeks.

The 200-metre long milky-coloured slick has been seen by cyclists and walkers floating on the surface of the canal between Jericho and Wolvercote in Oxford.

British Waterways, which manages the canal, is now sending in ecologists to find out whether the slick could be damaging to local wildlife.

Plans are also being put into place to clear it up.

Mark Lynas, of Wolvercote, spotted the residue floating on the surface of the canal while cycling along the towpath. He reported it to British Waterways.

He said: "There's sewage floating on the canal. I see it every time I cycle along the path and it lasts most of the way between Wolvercote and town.

"I've told British Waterways but it's still been there for about two weeks.

"It has an unpleasant gassy smell and moves up and down the canal as the wind blows."

John Ashby, chairman of Friends of the Oxford Canal Basin (Foxcan), said: "Everybody is worried about the pollution and sewage in the canal. It should be kept properly clean.

"All we can do is monitor the problems and let those who are responsible know."

British Waterways said investigations had not revealed any dead fish or wildlife.

Jane Marriott, supervisor for the South Oxford Canal, said: "We are going to carry out some more investigations because we don't know where it has come from.

"It may have been caused by dust from recent building works by the canal.

"We are bringing in ecologists to ensure it is not harmful to the fish or the waterlife.

"But because the water is slow moving and the canal reaches a dead-end nearby, there is not a lot of action in the water so it can be sitting there for a long time without moving on.

"If it is something we can clear up then we will. But at the moment we do not think it is dangerous.

"We appreciate and need members of the public contacting us if they see pollution like this."

Experts from British Waterways are investigating whether the slick is solid enough for them to use nets to clear or whether to place beams on the surface to soak up the waste.