Theresa May’s House of Commons defeat of her Brexit plan on 15 January 2019 has widely been reported in the British press as the largest defeat ever suffered by a UK government in modern times. She lost the motion by 434 votes to 202, a majority of 230 for the opposition. And yet numerous UK news outlets, some of them very prestigious, have made a fundamental error in their lists of other crushing defeats in the 20th century, citing the next three biggest as all being suffered by Ramsay MacDonald’s minority Labour government in 1924: two defeats of 166 and 161 votes on 8 October, and another of 140 votes on 23 June in the same year. This smaller defeat was a rejection of the government’s financing plans for what became the Wheatley Housing Act (1924), but the larger defeats both related to No Confidence motions brought by the Opposition on the same day. However, the mistake made by the British news corporations is that one of those ‘defeats’ was actually a victory.
Both votes on 8 October 1924 were connected by the same issue: the ‘Campbell Case’. John Ross Campbell was a young British communist who, through his newspaper Workers’ Weekly, appealed to the British armed forces to mutiny if called upon to shoot their “fellow workers”. It was a naïve letter written by an impulsive young man, but it brought a charge of ‘incitement to mutiny’ down upon his head, a crime that could attract a life sentence of penal servitude if he was convicted. The Left-wing Labour government was accused of putting pressure on the Attorney-General (Sir Patrick Hastings) to withdraw the charges because, in effect, this was taking a sledgehammer to crack a walnut, but MacDonald insisted that from a political and constitutional point of view, prosecutions – once begun – should be allowed to run their course. It was also pointed out that Campbell had won the Military Medal in the Great War for bravery, and Hastings (who was by now doubting the likelihood of a successful conviction) advised the Prime Minister that the case should be dropped.
This did not stop the combined opposition in the Commons from loudly accusing the government of being soft on communism, and on 8 October Sir Robert Horne (1871-1940) brought forward a Motion that the government should be reprimanded (‘censured’) by the House for allowing the Campbell Case to be dropped. After a vigorous debate in which the government defended itself admirably, this Motion was rejected by the House by 359 votes to 198, a victory majority of 161 for MacDonald but which the current British news outlets have claimed was actually a defeat for the government.

However, Sir John Simon (1873-1954), the Deputy Leader of the Liberal Party, brought forward a second Motion that changed the focus and emphasis of the first. He proposed that a committee be established to investigate the whole Campbell affair and the government’s part in it, and it was this vote that brought the government down by 364 to 198, a majority of 166.
It is likely that the modern mistake made by the Telegraph, the BBC, ITV News, the Guardian and many others lies in the fact that MacDonald regarded both votes as expressing No Confidence in the Government and asked the King for a dissolution of Parliament.
In the subsequent general election, the Conservatives won a handsome majority of 104 under Stanley Baldwin.
Useful sources:
Austen Morgan: J. Ramsay MacDonald (University of Manchester Press, 1987)
Hansard (1924): https://api.parliament.uk/historic-hansard/commons/1924/oct/08/attorney-generals-explanation