In many cases he took a strong position of his own, notably in that of Farrar v. Close (1869), which materially affected the legal status of trade unions and was regarded by unionists as a severe blow to their interests.

Hannen's last public service was in connection with the Bering Sea inquiry at Paris, when he acted as one of the British arbitrators.

In January 1891 he was appointed a Lord of Appeal in Ordinary with the dignity of a life peerage as Baron Hannen, of Burdock in the County of Sussex,[2] but in that capacity he had few opportunities for displaying his powers, and he retired at the close of the session of 1893.

[3] He died in London, after a prolonged illness, on 29 March 1894[1] and is interred in the catacombs of West Norwood Cemetery He was the elder brother of Sir Nicholas John Hannen who was Chief Justice of the British Supreme Court for China and Japan from 1891 to 1900 and concurrently British Consul General at Shanghai from 1891 to 1898.

[4] His son Henry Arthur, born 1861, was formally educated and became a justice of the peace lived in Smiths Hall in West Farleigh & was married.