Born in London. Daughter of the Canadian steel magnate Sir James Dunn, 1st baronet (1874-1956) and his second wife, Irene Clarice Richards, a former musical-comedy actress who had previously been married to Francis Douglas, 11th Marquess of Queensberry.

Dunn studied in London at the Chelsea School of Art (1949-50) and at the Anglo-French Centre (1952) under Henry Moore and guest artist Fernand Léger before going to the Académie Julian in Paris in 1952.

Dunn's first husband was the artist Michael Wishart (1928-1996) with whom she had one son, Francis Wishart, a painter and winemaker. In 1960 Dunn and Wishart were divorced and she married the Anglo-Spanish artist Rodrigo Moynihan (1910-1999) with whom she had a son Danny Moynihan, an artist and writer.

Her first solo exhibition was at the Leicester Galleries in 1957 with subsequent shows there in 1959, 1960, 1962 and 1964. Thereafter she exhibited regularly at the Fischbach Gallery in New York from 1967-1989

In 1990 Dunn had an exhibition at the Christopher Hull Gallery in London and in 2005 at the Tibor de Nagy Gallery in New York.

Collections
Arts Council of Great Britain
Contemporary Art Society (Annual Report 1957-8)
The Financial Times
Government Art Collection
Carlisle Museum and Art Gallery
American Telephone and Telegraph Corporation, New York
Chemical Bank, New York
Columbus Museum of Art, Columbus, Ohio
Commerce BankShares Inc., Kansas City Missouri
Hess Corporation, New York
Xerox Corporation, New York
Art Center, University of New Brunswick, Federation, New Brunswick
Bank of Novia Scotia, Federicton, New Brunswick
Beaverbrook Art Gallery, Fredericton, Nnew Brunswick
Harriet Irving Library, University of New Burnswick, Fredericton, New Brunswick
New Brunswick Provincial Art Bank, Federicton, New Brunswick