Thousands of fish have died after a major pollution mishap in Lincolnshire.

The Environment Agency says 10 miles of the River Slea near Sleaford have been polluted by a pesticide spill.

The incident happened on Sunday between Sleaford and South Kyme.

Peter Clarricoates, a retired Environment Agency worker, told BBC Online that it was "nasty" incident.

Dace and pike

The agency has traced the leak to a company in Sleaford and identified the pesticide as cypermethrin, which is used widely in the farming industry as a general crop pesticide.

"I have seen dead fish and eels all over - everything in the river seemed dead," said Mr Clarricoates, who lives in the area.

The river was stocked with dace, pike, roach and trout, he said.

The Environment Agency is cleaning up the river after the category-one incident.

Other eyewitnesses reported seeing hundreds of dead fish lying on the riverbed over an extended length of the river.

Five years ago, a similar incident in Wiltshire wiped out the crayfish population in the River Avon when a quantity of the pesticide spilled into the river.