 On graduating in 1960, he began work on his PhD under the supervision of Peter Whittle, studying queueing theory, Markov chains and regenerative phenomena.Whittle left Cambridge for the University of Manchester, and, rather than follow him there, Kingman moved instead to the University of Oxford, where he resumed his work under David Kendall.After another year, Kendall was appointed a professor at Cambridge and so Kingman returned to that other University.