Boothby was an unsuccessful parliamentary candidate for Orkney and Shetland in 1923 and was elected as Member of Parliament (MP) for Aberdeen and Kincardine East in 1924.

[5] In 1954 (echoing words he had said in 1934), Boothby complained that for 30 years he had been advocating "a constructive policy on broad lines" but that this had not been taken up: "The doctrine of infallibility has always applied to the Treasury and the Bank of England".

Boothby opposed free trade in food stuffs, and claimed that such a policy would invalidate the Agriculture Act 1947 and ruin British farmers.

By making them feel that, instead of unfortunates they are social pariahs, you drive them into squalor – perhaps into crime; and produce that very "underground" which it is so clearly in the public interest to eradicate.

[11]Boothby premised his argument for law reform on the idea that it was the role of the state "not to punish psychological disorders – rather to try and cure them".

[17][18][19] This connection to Macmillan, via his wife, has been seen as one of the reasons why the police did not investigate the death of Edward Cavendish, 10th Duke of Devonshire, who died in the presence of suspected serial killer John Bodkin Adams.

His second cousin, writer and broadcaster Sir Ludovic Kennedy, asserted that Boothby fathered at least three children by the wives of other men ("two by one woman, one by another").

[24] He later spoke about the role of a speculated homosexual relationship in the drowning of his friend Michael Llewelyn Davies (one of the models for Peter Pan) and fellow Oxonian Rupert Buxton.

[24] In 1963, Boothby began an affair with East End cat burglar Leslie Holt (d. 1979), a younger man he met at a gambling club.

[24] When Boothby's underworld associations came to the attention of the Sunday Express, the Conservative-supporting newspaper opted not to publish the damaging story.

[26][27] The matter was eventually reported in 1964 in the Labour-supporting Sunday Mirror tabloid, and the parties were subsequently named by the German magazine Stern.

[24] The police investigation received no support from Scotland Yard, while Boothby embarrassed his fellow peers by campaigning on behalf of the Krays in the Lords, until their increasing violence made association impossible.

[citation needed] The MI5 files focus on Lord Boothby, who was said to share Ronnie Kray's fondness for young men.

Unlike some who were impressed by Hitler, Boothby came away thinking he had seen "the unmistakable glint of madness in his eyes," and the meeting helped convince him to become one of Churchill's small group of parliamentary campaigners for faster rearmament.

[30] After his death from a heart attack in Westminster Hospital, London, aged 86, Boothby's ashes were scattered at Rattray Head near Crimond, Aberdeenshire, off the coast of his former constituency.