The defendant maintained two lagoons on his land into which, pursuant to an agreement, the owners of adjoining land discharged effluent. The lagoons developed leaks which allowed the effluent to escape into the river.
Held: The escape had not been caused by anything which the defendant had done. There was no ‘positive act’ on his part. The effluent came onto the land by gravity and found its way into the stream by gravity ‘with no act on his part whatever:’
Lord Widgery CJ
 1 WLR 988,  2 All ER 113
England and Wales
Disapproved – Empress Car Company (Abertillery) Ltd v National Rivers Authority HL 22-Jan-1998
A diesel tank was in a yard which drained into a river. It was surrounded by a bund to contain spillage, but that protection was over ridden by an extension pipe from the tank to a drum outside the bund. Someone opened a tap on that pipe so that . .
Gazette 26-Feb-98, Times 09-Feb-98, Gazette 25-Mar-98,  2 WLR 350,  UKHL 5,  2 AC 22,  1 All ER 481
Restricted to its facts – National Rivers Authority v Yorkshire Water Services Ltd HL 21-Nov-1994
The defendant sewerage undertaker received sewage, treated it in filter beds and discharged the treated liquid into the river. One night someone unlawfully discharged a solvent called iso-octanol into the sewer. It passed through the sewage works . .
Independent 01-Dec-94, Times 21-Nov-94,  1 AC 444,  3 WLR 1202,  1 All ER 225
These lists may be incomplete.
Updated: 15 December 2020; Ref: scu.190103