He was a long-standing and early member of the Conservative Monday Club, serving on several of its committees. He was a member of the Club's Executive Council in 1971, when he became Chairman of their 'Action Fund', and elected National Chairman on 5 June 1972, fighting off challenges from Richard BodyMP, and Timothy Stroud. The Guardian and The Times referred to his election as "a right-wing victory". At the Club's Annual General Meeting in April 1973 Guinness retained the Chairmanship for another year, defeating George Kennedy Young. In mid-1974 he was invited to address Conservative students at Portsmouth Polytechnic, but was prevented from doing so by protesters. On 10 October 1989, at the Conservative Party Conference, he chaired a controversial fringe meeting organized by the Young Monday Club, advertised as The End of the English? - Immigration and Repatriation. The other speakers were MPs Tim Janman and Nicholas Budgen. As Chairman of the Club's Race Relations & Immigration Committee, he also wrote the same month to all Club members; "There has been a lot of ill-thought out agitation following events in China, urging the government to amend the British Nationality Act so as to give the right of UK residence to more than three million people from Hong Kong who hold British passports. At the time of writing the government has stayed firm on this, but it is under pressure. If you have not already done so, please write to your M.P., your local and national newspapers, or the Prime Minister expressing support for the government's stand. Remember, a passport is not a residence permit, but a travel document; and think of the sheer physical burden of housing and accommodating a sudden influx of this size." He was also Club Vice-Chairman until late 1990 when he was replaced by Andrew Hunter, MP.
Trustor
Lord Moyne was accused of involvement in a Swedish financial scandal. The case concerns a now defunct Swedish investment company, Trustor, of which Lord Moyne was made a figurehead director. It was alleged that Guinness was involved in the disappearance of £50,000,000 from Trustor's accounts, £35,000,000 of which were soon found on Trustor AB:s own bank account as they had never left the company. Guinness maintained that he was innocent of any wrongdoing, claiming he has been "stitched up". During the proceedings, Swedish authorities were successful in obtaining a freezing order over what little assets he had left. He was found innocent by the Swedish court.
Lord Moyne has spoken in support of the Falun Gong movement in China since it was banned there in 1999, as reported in Hansard.
Director of Guinness plc
Lord Moyne was a non-executive director from 1960 to 1988 of the company set up by his family. His book Requiem for a Family Business gives an uninvolved insider's account of the corporate developments leading to the Guinness share-trading fraud.
Personal life and family
Lord Moyne has been married twice and has eight children. He married firstly, in 1951, Ingrid Wyndham, later the wife of Lord Kelvedon, with issue:
The Honourable Valentine Guy Bryan Guinness, heir apparent to the Barony of Moyne, who was married to handbag designer Lulu Guinness and has two daughters. They were separated in 2004, and divorced in 2013.
Lord Moyne married secondly, in 1964, Suzanne Lisney, with issue:
The Honourable Sebastian Walter Denis Guinness, who has been twice married without issue. The heir presumptive to the Barony of Moyne.
By his mistress Susan "Shoe" Taylor, Lord Moyne has the following issue:
Diana Guinness
Aster Guinness
Thomas Guinness-Taylor
To avert a scandal over the extramarital affair with Taylor, Lord Moyne published Shoe - The Odyssey of a Sixties Survivor in 1989. The Sun newspaper ran a double-page article with pictures entitled Always a Mistress - Never the Bride on 6 July 1989. Moyne and his daughter Daphne both had letters published in the same edition of The Daily Telegraph attacking the writer Andrew Roberts over his criticism in the same newspaper on 13 August 2003 of Jonathan's mother, Lady Mosley, following her death.