The parliamentary return for Hampshire and its boroughs in 1429 names the MPs for Portsmouth as Richard Hunt* and John ‘Garton’, but no-one with the latter name has been found to fit the bill satisfactorily. It therefore seems likely that this was a mis-spelling of Garston, and the man elected was the John Garston who lived across the Solent from Portsmouth on the Isle of Wight. Whether he was a native of the island has not been discovered, but he had been living there from at least the early 1390s, and in the course of his career had established himself as a landowner of some substance.
Garston’s rise to prominence stemmed from a long involvement with the affairs of monastic houses on the Isle of Wight, in particular the Cistercian abbey of Quarr, from which in 1393 he and his wife leased a croft in Arreton.
Garston was regularly appointed by the Crown as a collector of parliamentary subsidies, his brief probably being to collect dues on the island rather than elsewhere in Hampshire. When Henry V was commencing preparations for his invasion of Normandy in the spring of 1415, with the embarkation of his forces planned to take place across the water at Portsmouth, Garston was among those commissioned to array the able-bodied men living on the island for its defence. His motivation for seeking election to the Parliament of 1429 remains obscure, and nothing has been found to link him with his fellow MP for Portsmouth, Richard Hunt, who also seems to have been an outsider to the town. Parliament met for two sessions. During the first, in November, the young King Henry VI was crowned; the second prepared for his coronation expedition to France, and closed on 23 Feb. 1430. On the following 19 Apr. Garston conveyed to John Whyte and his wife and son a tenement and two shops in Newport, together with a parcel of meadow in Whippingham, in return for an annual rent of 27s.
Garston had wished to found a chantry at Newport in honour of the Virgin, to provide religious services for the masters and mariners of ships wintering in the shelter of the harbour while waiting for favourable winds to sail to Aquitaine and Bordeaux for cargoes of wine and other merchandise. He had noticed that the chaplain engaged to administer to these shipmen in the existing chapel, situated some distance from the parish church, was often through absence or infirmity unable to perform his duties, so that sailors and women in childbirth had died without confession and infants without baptism; his proposed foundation would supply an additional chaplain. To make the endowment he had placed certain lands in the hands of feoffees, including Whyte, but had been unable to complete the project before he died. It was not until some 19 years after his death that, on 26 Jan. 1449, the feoffees obtained royal licence to grant the chantry lands worth 20 marks a year in mortmain. It was to be called the chantry of John Garston and John Whyte, and prayers were also to be said there for the King and queen.
