He was the descendant of Anglican clergymen through both parents: his paternal grandfather (John Howson) was Dean of Chester, and his maternal great-grandfather (Thomas Dealtry) was Bishop of Madras.
Having been promoted to captain, he was awarded the Military Cross for his actions at Pilckem Ridge in the Battle of Passchendaele on 31 July 1917, where, despite receiving a shrapnel wound, he encouraged his unit to continue repairing a road under shellfire.
Howson started with a workforce of five disabled ex-servicemen at a former collar factory on the Old Kent Road in June 1922.
The Disabled Society merged with the British Legion in 1925, and the Poppy Factory became a company limited by guarantee, with Howson as chairman.
The factory moved to Richmond, Surrey in 1926, to the premises of an old brewery bought using money donated by Howson.
He was buried at Hambleden, with the funeral service conducted by his father, by then an archdeacon and canon emeritus of Liverpool Cathedral.