Chemicals were accidentally hosed from a runway into a stream

Gatwick Airport Ltd had already admitted letting the chemicals enter the River Mole in September 2002.

A fine of �30,000 was set at Lewes Crown Court after the prosecution was brought by the Environment Agency.

As many as 8,000 fish of 14 species died when the chemicals used to clear rubber and oil foamed up and then were washed into the river by a water hose.

Unblemished record

At an earlier hearing before Haywards Heath magistrates in November 2003, the court heard how the number of fish killed were about three-quarters of those in the area.

The detergent was not often used at the airport and when it unexpectedly foamed up it had to be cleared quickly so planes could land safely.

The unintentional result was that the chemicals flowed into the River Mole via a brook, the court heard.

Sentencing the airport, Judge David Rennie said the company had a previously unblemished record before the incident.

He said procedures had been put in place to prevent it being repeated but the error made by the airport had been something more than carelessness.

The case was referred to the crown court for sentencing after magistrates decided their powers, which allow them to impose a fine only up to �20,000, were insufficient.