Hannagan and Devereux was established in 1957 by Brian Hannagan with John Devereux becoming partner in 1964. Tim Hannagan joined the practice in 1981 and became a partner in 1988. John Sneddon joined the firm in 2001 with a history in the finance industry and became a partner in 2009. Since establishment, the firm has enjoyed significant growth and success due to its ability to retain clients and deliver consistently superior services.