The by-election was held due to the resignation of the incumbent Coalition Unionist MP, Robert Francis Peel.It was won by the Coalition Unionist candidate Sir Arthur Churchman.The by-election was caused by the sitting Unionist MP, Robert Francis Peel resigning his seat to become Governor and Commander-in-Chief of St Helena.The Coalition Government 'Coupon' at the last General Election in 1918 was awarded to the sitting Unionist rather than the Liberal challenger.Despite this, the Liberal vote held up very well; Polling Day was set for 28 July 1920.