During the inter-war period, Prior-Palmer took an interest in equestrianism while continuing in service with the Lancers. He owned a stud which bred horses for the WarwickshireHounds, although he sometimes had to sell up when his leave was cancelled and he was posted abroad. He also enjoyed sailing in the late 1920s, and was a member of the Royal Yacht Squadron. In July 1926 he married Hon. Barbara Frankland. His interest in horses was also manifest in horse racing: he was at first a jockey. In the Sandown ParkGrand Military Gold Cup of 1932, he rode "Master of Orange" and led in the early stages, before coming in second at the finish. Later he was an active trainer of race horses.
Promotion
In March 1936, Prior-Palmer was promoted Major. However, he sued for and was granted a divorce in 1936 on the grounds of his wife's adultery with the 5th Earl of Normanton, whom she subsequently married. On 11 May 1940 Prior-Palmer took as his second wife, Sheila Weller-Poley. His second wife was to be active in politics later as a Conservative and as Chairman of West Sussex County Council Education Committee.
At the 1945 general election, Prior-Palmer was adopted as the Conservative Party candidate for Worthing, a new constituency which had been created in boundary changes just before the election. He was placed on retired pay by the Army in 1946 with the honorary rank of Brigadier. In Parliament, Prior-Palmer began his career by voting against the large loan from the United States which the Labour government had negotiated after the end of Lend-Lease. However, these were the only dissenting votes he ever cast against the Conservative whip. In 1946 he argued for retaining conventional defence in addition to nuclear arms, because an answer would be found to the atomic bomb.
Contribution to debates
With an interest in army training and the cadet services, in May 1947 Prior-Palmer moved a new clause to the National Service Bill which would give an incentive to those who were called up for National Service after achieving a level of efficiency in the cadets. In March 1948 he went on a Parliamentary delegation to East Africa. Later that year he warned of the danger of invasion of the United Kingdom by air, and urged the creation of a force to tackle it.
Outspokenness
His constituency was safely Conservative and Prior-Palmer had a majority of over 21,000 in the 1951 general election. In the first month of the new Parliament, with a Conservative government once again, he was required to apologise after being overheard saying that the Labour frontbencher and former Minister Jim Griffiths "had never done a damned day's work in his life". In May 1953 he launched a debate on the need for voluntary defence services. In September 1954 he was named on a delegation to visit the Soviet Union.
Prior-Palmer supported abolition of capital punishment in an unwhipped House of Commons vote in February 1956, one of only 48 Conservative MPs to do so. He backed the Eden government on Suez, arguing that it took British and French intervention to get a United Nations force to come in. Having served as Chair of the Conservative Backbenchers' Army sub-committee for most of the 1950s, he was made Vice-Chairman of the Defence Committee from 1958.
Elder statesman
in 1959, Prior-Palmer was regarded as an 'elder statesman' but could still be angered by pacifist sentiment. In February 1960 he claimed that the Labour Party had "sent one of their chief leaders to Swaythling to stop men making Spitfires". Despite uproar among Labour MPs present, he refused to withdraw. In February 1961, Prior-Palmer signed, but later withdrew his name from, a motion critical of the constitutional development of Northern Rhodesia.
Retirement
On 7 November 1963, Prior-Palmer announced that owing to "personal reasons and reasons of ill-health", he would not be a candidate at the next general election. He had in the meantime become involved in business in the field of commercial radio, as an investor. In 1964 he divorced his second wife and married his third, Elizabeth Henderson. They had two sons in the mid-1960s.