 Prendergast won prizes at the National Eisteddfod in 1975 and 1977.Examples of his paintings are owned by the Contemporary Art Society of Wales, and the Tate Gallery.For some years his work was shown by Agnew's gallery in London, culminating in a touring exhibition; the foreword to the exhibition catalogue was written by Sister Wendy Beckett, who described him as "a superb colourist and a master of form".