Mahoney was asked to contribute to the Festival of Britain after an initial shortlist of 145 artists was narrowed down to 60.  Percy Jowett and John Rothenstein, members of the selection panel, undoubtedly would have recommended him. The exhibition was entitled Sixty paintings for ’51. Works submitted were to be a minimum of 45 x 60 in. The oldest artist asked was W G Gillies (73 at the time), the youngest Lucian Freud (29).  Other artists selected included John Armstrong, Edward Burra, Ivon  Hitchens, L S Lowry, John Minton, William Scott, Keith Vaughan, Carel Weight and Rodrigo Moynihan ; Barnett Freedman and Edward Bawden, both also invited, declined.

Mahoney’s contribution was entitled The Garden. Figurative works accounted for approximately half of the contributions submitted and many, like Mahoney’s, were firmly rooted in the British tradition of landscape painting. A full account of the exhibition is given in 25 from 51, 25 Paintings from the Festival of Britain 1951, Sheffield City Art Galleries, 1978