Andrew Wilkinson of Manor Farm, Fearby, Harrogate, and Nigel Wilkinson of Manor Farm Cottage, Low Ellington, near Masham, admitted the charges and were each ordered to pay £615 in costs to the Environment Agency, which brought the case.

The court heard that, following a phone call from a member of the public on 22 November 2004, Environment Agency officers discovered an oil sheen on the River Ure at Masham. William Wilkinson, father of the defendants, also rang to say there had a been a leak from a fuel tank.

Officers visited Manor Farm at Low Ellington, and discovered that a metal fuel tank was leaking from a hole that had been plugged with a screw and a piece of cloth.

It was later estimated that around 400 gallons of red diesel had leaked from the tank. An inspection revealed there was no protective bund around the tank to prevent the spread of leaks and no locking mechanism on the tank or filler hose.

The officers followed a culvert which led to Broad Beck and thence to the River Ure. The diesel pollution persisted as far as, and into, the Ure. A bio-survey carried out after a further visit revealed that most aquatic life in Broad Beck had been killed up to one kilometre downstream of the leak, and there were 35 dead fish.

Officers laid booms across the beck to catch the remaining diesel, and William Wilkinson arranged for a vacuum tanker to remove as much of the accumulated diesel from the water and yard as possible.

In mitigation it was said that the Wilkinsons had paid the costs of the cleanup, which came to £2,824, and that they believed that the leak had been the result of an act of vandalism.

A Reverend Cleeves appeared in court as a character witness testifying on behalf of Andrew Wilkinson.