The levels of cyanide in a Walsall canal impacted by a major chemical spill have “improved”, according to the organisation leading the clean-up operation.

About 4,000 litres (879 gallons) of sodium cyanide and other chemicals leaked into the canal on 12 August, closing a 12-mile stretch of the waterway and killing thousands of fish.

A clean-up operation by the Canal and River Trust (CRT) is underway, after it raised more than £20,000 to fund the work.