This avenue was named after William J. Twaddell, who was a draper, in North Street in Belfast. He was also a member of the first Northern Parliament. He was assassinated on Monday May 22, 1922 in Lower Garfield Street. Whilst no one has ever been charged with his murder, there are various suggestions who may have been responsible for his killing. In his book, John J. Marshall states he was killed by "three young men who hid in a cul-de-sac at the rear of Mayrs' (now Sinclair's premises) and shot him as he was passing to Royal Avenue from his place of business".
"Naming Scheme – Street Names
Read the following resolution passed by the Housing Committee at their meeting on the 14th inst.:
(Copy)
"Street Names, Woodvale Site."
Submitted and read minute of the Improvement Committee of 11th inst., approving of the names suggested by this Committee for the new streets on the Woodvale site except “Crumlin Avenue” for which that Committee propose the substitution of the name “Twaddell Avenue.”
The City Surveyor having reported on the matter, it was resolved that the Improvement Committee be informed that this Committee are of the opinion that the name “Crumlin Avenue” should remain, and suggest that “Twaddell Parade” be substituted for “Woodvale Parade.”
Moved by Councillor Henderson
Seconded by Councillor S. Gray, and Resolved that this Committee reaffirm their previous recommendation suggesting that the name “Twaddell Avenue” be substituted for that of “Crumlin Avenue,” and that the above-mentioned resolution be referred back to the Housing Committee for reconsideration". (25th September 1923).
Historian Jason Burke in his popular podcast Historical Belfast devotes an episode to North Street and includes details of the assassination of William Twaddell in 1922. Twaddell had been elected the previous year as the Member for West Belfast of the Northern Ireland Parliament.
https://www.buzzsprout.com/1047775/episodes/15418539-exploring-north-street