A distinguished army officer with literary and parliamentary ambitions, Donkin had been born into a respectable Northumbrian family of Scottish descent, and at the age of five, been entered into the army by his father, who then held the rank of major in the 44th Foot.
After the death of his first wife in 1818, Donkin, suffering mental distress, was invalided to the Cape where, following his recovery, he assumed the governorship of the colony during the absence of Lord Charles Somerset in 1820. Although his tenure was brief, he gained plaudits for his decision to diverge from Somerset’s policies for the establishment of settlers. Upon resuming his post, however, Somerset reversed Donkin’s decisions.
Connected to the region by his ancestry, at the 1832 general election Donkin offered as a Liberal for Berwick-upon-Tweed, where, following a fractious contest, he topped the poll. A frequent attender in his first Parliament, he followed the Whigs into the division lobby on most major issues, and, after his return in second place at the 1835 general election, voted for Abercromby as speaker, 19 Feb. 1835, and for Russell’s motion on Irish church appropriation, 2 Apr. 1835.
As an expert on military matters, Donkin confined his handful of known speeches to addressing army issues. He spoke in favour of retaining military flogging, stating that although the best ‘way to preserve discipline in the army was to appeal to the moral feelings of the soldiers’, if that failed, the only other method ‘was to have recourse to physical suffering’, 2 Apr. 1833. He also intervened in debates on supply, opposing any reductions in the army estimates, 3 Mar. 1834, 22 May 1835, reiterating the position he had previously outlined as a witness on the 1833 select committee on military appointments.
At the 1837 general election Donkin, who was roundly criticised for his vote to remove the rights of freemen in the government’s municipal corporation bill, 23 June 1835, endured a hostile campaign and was defeated by two Conservative candidates.
By the beginning of 1841, Donkin’s poor health had precipitated a severe depression, and he was unable to discharge his duties as surveyor-general. After arriving in Southampton in April that year for a change of air, he hanged himself at his apartment on 1 May, with the coroner returning a verdict of temporary insanity.
