Herbert Horatio Spencer Westmacott, known as Spencer, was born in Christchurch, New Zealand, on 10 November 1885, to a middle-class family of limited means. His mother, Ada Janet Depree, was of Huguenot descent. She had defied her family to marry Herbert Westmacott, in preference to the more affluent gentlemen approved by her solicitor father. Spencer entered Christchurch Boys' High School in 1896; there as a bugler he commenced a long association with soldiering. From 1900 to 1903 he attended Waitaki Boys' High School, where he went into camp with the Waitaki Mounted Rifle Volunteers.
On leaving school Westmacott worked at Waikakahi on the farm that his father had drawn in a ballot after managing the Stonyhurst and Flaxbourne runs for Frederick Weld and Charles Clifford. From 1910 to 1914 he cleared a bush farm east of Te Kuiti and Otorohanga, enduring the rigours, frustrations and loneliness of such a life.
Westmacott began a military career when he became a second lieutenant in the 16th (Waikato) Regiment in April 1912. In 1913 he was one of the farmers who travelled to Auckland to break the waterfront strike. In October 1914 he went to Egypt as a platoon commander with the Auckland Battalion to join the New Zealand Expeditionary Force. During the Gallipoli campaign he received a terrible wound under his right armpit, as a consequence of which he lost the arm, and also suffered a back wound on the campaign's first day. He spent months in hospitals and convalescent homes in Egypt and England, often in the residences of the wealthy and aristocratic people who had opened their homes to wounded officers.
Early in 1917 Westmacott joined NZEF headquarters, London. He soon came to despise most of the staff, who, he thought, had little commitment to front-line duties and much to the safety and comfort of the rear. In April he gladly went to France on appointment to a training position, specialising in open warfare. He was there for the rest of the war and was involved in helping to stem the German advance in March 1918, although he was not allowed at the front because of the loss of his arm. Appointed an OBE and mentioned in dispatches, he finished his war service as a temporary major, reverting to captain in the Territorial Force from which he retired as major in 1934. He was awarded the Efficiency Decoration.
In London, on 17 September 1918, Spencer Westmacott married Jean Patricia Campbell, the daughter of Christchurch family friends, whom he had known since childhood and met again during his convalescence. For a period she had served as a volunteer nurse in France. Throughout his memoirs he writes of her with fondness and respect. They were to have two daughters and one son.
On his return to New Zealand Westmacott attended the Canterbury College School of Art from 1920 to 1925 and was secretary of the Christchurch Club from 1920 to 1924. In 1927 he resumed the management of his King Country property, where he remained until retiring to Wellington in 1958. During the Second World War he raised and commanded the Otorohanga Battalion of the Home Guard.
Despite being maimed, Westmacott wrote, farmed, soldiered, rode, shot, and painted and sketched. He is reported to have been a talented artist before and after being wounded. He painted many watercolour landscapes in the North and South Islands, and produced paintings of his army days and a full-length oil portrait of his father in 1925. There is also a sketch of the Gallipoli landing in the Queen Elizabeth II Army Memorial Museum at Waiouru.
In 1938 he commenced his extensive memoirs. Selections from these were posthumously published as The after breakfast cigar; they are lucidly written and include lively descriptions of people. They are a key source on pioneering work, people and life in the King Country when it was first opened for Pakeha settlement.
When he died in Wellington on 26 January 1960, survived by his wife and children, Westmacott left 2,200 acres in the King Country and property in England. Described in 1917 as 'a very determined and reliable Officer with a cheerful disposition, tactful and well balanced', Spencer Westmacott exemplified the values of optimism, determination, fortitude and loyalty to the British Empire. He had the ability to apply himself to any task required and to perform it competently. His memoirs are a bonus.