His most notable result was at the 1851 London tournament, in which he defeated the celebrated British player Howard Staunton in the play-off for third place.
According to Staunton, following a particularly dilatory performance by Williams in the London 1851 tournament, a 20-minute per turn time limit was adopted for standard play the next year.
However other sources contradict this viewpoint and indeed it was not uncommon for Staunton to attribute his losses to the intolerable dilatory play of his opponents.
In The Complete Chess Addict by Mike Fox and Richard James, he was dubbed "the Bristol Sloth" due to his alleged extreme slowness.
This sobriquet inspired a musical tune "The Bristol Sloth" by guitarist Leo Kottke (who also applied the term 'sitzkrieg' in describing Williams' playing style).