Weigall was the fifth son of a Victorian artist, Henry Weigall (best known for his portrait of Benjamin Disraeli in 1878–1879), and his wife, Lady Rose Sophia Mary Fane, daughter of John Fane, 11th Earl of Westmorland, and wife Priscilla Anne Wellesley-Pole.

[1][2] His father was born in Denmark, of Danish and English descent,[3] son of Poul Arkner, born Poul Christian Anderson (b. Denmark) and wife Pamela Joyce Weber (b. Hertford, Hertfordshire), daughter of Reginald Evelyn Weber and wife Joyce Warner.

He was promoted to captain on 4 April 1902,[4] when the battalion left for South Africa as reinforcement for what turned out to be the last stages of the Second Boer War.

[5] Following the end of the war in June 1902, Weigall and the other men of the 3rd battalion left Cape Town on the SS Scot in early September, and returned to Northampton after arrival in the United Kingdom later the same month.

In World War I, he served with the Northamptonshire Regiment and on the Staff, finishing with the rank of lieutenant colonel.

The by-election was caused by the sitting Conservative MP Lord Willoughby de Eresby, who had held Horncastle at each election since 1895,[7] succeeding to the peerage on the death of his father, the Earl of Ancaster.

He very quickly became disenchanted with the State Parliament; he became extremely frustrated with the way in which ministers would spend money before being granted supply, or transfer funds voted for one purpose to another.

[8] Weigall sought leave to resign in December 1921, citing "personal and financial" reasons.