Leonard Dunning was born on 17/06/1860 in London.
He was educated at Eton and graduated at Exeter College, Oxford with honours in 1881. In 1882 he joined the Royal Irish Constabulary and rose through the ranks to District Inspector.
In 1894 the position of Assistant Head Constable became available in Liverpool. Out of 67 applicants Dunning was selected and appointed on 17/12/1894.
In 1902 he was appointed as Head Constable on the retirement of Nott-Bower.
In January 1911 Dunning was awarded the King's Police Medal.
He retired as Head Constable in December 1911 and was then appointed as His Majesty's Inspector of Constabulary.
On 21st February 1917 he was knighted. He retired in 1930 and was created a baronet.
Dunning died on 08/02/1941 aged 80yrs.