Clifford, Mary (‘Mai’) (née Hollingsworth ) (1913–86), trade union official and laundress, was born 25 September 1913 at Phoenix Park, Glasgow, Scotland, the elder of one daughter and one son of Joseph Hollingsworth, a blacksmith from Co. Kerry, and his wife Elizabeth, a Glasgow native. The family moved to Ireland in 1915, residing in Co. Dublin, first at Leinster Square, Rathmines, and then at Mill Forge, Templeogue. Both her parents were strong supporters of labour leader James Larkin (qv). Educated at St. Joseph's convent, Terenure, Mai joined the Irish Women Workers’ Union (IWWU), two days after beginning employment at age fifteen in the Terenure Laundry, and soon was elected shop steward. Throughout her trade-union career she placed matters of health and safety, and the quality of working and social life, high on the agenda. In 1945 she led her workmates off the job as part of an IWWU strike of 1,500 workers against Dublin commercial laundries in pursuit of a second week's paid holidays per year. Winning their claim from the Federated Union of Employers after a fourteen-week stoppage (during which Clifford supported her unemployed husband and two young children on strike pay of five shillings per week), the laundresses were the first workers in the country to wrest this provision from employers. After the closure of the Terenure Laundry, she worked in the Shelbourne Hotel, moving in 1957 to St Luke's Hospital, Rathgar, where she was supervisor in the linen room until her retirement in 1983.
Elected to the IWWU executive committee (1956), she served as the union's president (1973–5). She regularly represented the IWWU at annual delegate conferences of the Irish Congress of Trade Unions, and served on ICTU's standing orders committee. Throughout the 1960s–70s she campaigned for equal pay and promotional prospects for women. Appointed in 1970 to the women's advisory committee of ICTU, she was vigilant in opposing any hint of elitism within the movement by way of preferring professional women over industrial workers. In her presidential address to the IWWU's 1973 annual convention, she urged women to demonstrate the equality of their work and ability to that of men by embracing flexibility in the workplace, and accepting all available opportunities to augment their role. She travelled widely in Europe as a union delegate examining the status of working women in other countries. In Moscow in 1976 she met Mikhail Gorbachev, then USSR minister for agriculture. This provoked controversy when she stood unsuccessfully as Labour party candidate in the 1979 local government elections in the Crumlin–Terenure ward, and was denounced as a communist by a local priest.
A member of the executive of the Dublin Council of Trade Unions from 1971, Clifford served as the council's president (1978–81), the first woman elected to the office. In this capacity she was prominent in the trade unions’ income tax reform campaign of 1979–80, spearheaded by the local trades councils, and protesting the excessive level of taxation borne by the PAYE worker compared with the self-employed. Conspicuous in media coverage of the campaign, she led protest marches and gave rousing platform speeches, culminating on 22 January 1980 when 300,000 workers marched in Dublin, and nearly one million throughout the country, the largest demonstration by organised labour in the history of the state. Named IWWU honorary treasurer in 1983, after the union's merger with the Federated Workers’ Union of Ireland in 1984 she became an FWUI executive member and trustee.
She married (1936) Daniel Clifford (d. 1963), a builder's labourer, who played League of Ireland football professionally in the later 1930s; they had two sons. They resided with his family in Crumlin, first at 1 Windmill Lane, then moving in the mid 1940s to 14 Monasterboice Rd, her home for the rest of her life. She died 11 March 1986 at the Royal City of Dublin Hospital, Baggot St., and was buried in Templeogue cemetery.