Singleton was born in St Michael's on Wyre, Lancashire, and was educated at Lancaster Royal Grammar School[1] and Pembroke College, Cambridge, where he read Law, obtaining a third-class degree.
[2] Singleton was appointed a judge of the King's Bench Division of the High Court in 1934, receiving the customary knighthood.
The prosecutor on that case was Joseph Cooksey Jackson, who had also attended Lancaster Royal Grammar School.
[4] During World War II, he was asked by the Cabinet to report on the effectiveness of the Royal Air Force's strategic bombing campaign.
Richard Crossman, who also served on the Committee, described Singleton as being 'intensely loyal to what he conceived to be the interests of the [British] government'.