The firm can trace its history at Deal back into the 19th Century beginning with John May who, in about 1810, took John Mercer into partnership. After John May’s death, Mercer’s son George and his son-in-law James Barber Edwards joined the firm, practicing successfully as May & Mercer. After being articled to George Mercer, John James Williamson became a partner in 1885. In 1891 he dissolved the partnership and began to practice on his own. His wife’s nephew Reginald John Barnes was articled to him in 1929 and joined him as a partner in 1934. From that date the firm’s name of Williamson & Barnes has remained unchanged.

The firm has occupied the same offices at 12 & 14 Queen Street (formerly 19 & 20 Five Bells Lane) in Deal ever since 1803. 14 Queen Street looks like a bank, because it originally formed the banking hall of Messrs May, White, Wybourne & Mercer.

J.J Williamson acted as Clerk to the Deal Borough Justices followed by John Barnes in 1938 until Deal lost its separate commission of the peace in 1974.

The current partners are Michael Griffiths who was articled to the firm in 1983 and became a partner in 1987, his brother Jonathan Griffiths who joined the firm in 1996 became a partner in 2002 and Nathan Bowles who joined the firm in 2001 and became a partner in 2004.