The House of Lords overruled (modified)
Addie v Dumbreck [1929] AC 358.
In Addie, the House of Lords had held that an occupier of premises
was only liable to a trespassing child who was injured by the
occupier intentionally or recklessly. In Herrington, their Lordships
held that a different approach was appropriate in the changed social
and physical conditions since 1929. They propounded the test of
'common humanity' which involves an investigation of whether the
occupier has done all that a humane person would have done to
protect the safety of the trespasser.
The House of Lords
Occupiers Liability Act 1984
The child had got through a gap in the fence near the railway line. The board, as occupiers, were aware of previous trespasses but had failed to maintain the integrity of the fence.
The board was held liable for injuries to a six year old child who had been playing on the railway line. The House of Lords held that the occupier of the railway premises owed a duty of common humanity to the child. Until this case no duty of care was owed to trespassers. (The Occupiers Liability Act 1984 extended the duty of care to include trespassers).
Overruled Addie & Sons v Dumbreck [1929] Link
In Addie, an occupier of premises was only liable to a trespassing
child who was injured by the occupier intentionally or recklessly.
Full text
http://www.swarb.co.uk/c/hl/1972BRB_Herrington.html