David de Mardt, who was due to assume the role this month, has resigned for family reasons.
De Mardt established Pernod Ricard South Africa in September 1994 and had been holding the position of MD since then. He had previously founded Whiskeys of the World, which imported and distributed group brands in South Africa.
His appointment to the UK business, made in July, marked one of many management changes in Pernod's hierarchy in line with its policy of internal promotion and international mobility. The company named UK MD Jean-Manuel Spriet new MD of Pernod Ricard Korea and Irish Distillers chairman and chief executive Alexandre Ricard became MD of Pernod's group distribution network.
The changes coincided with a similar shake-up at rival Diageo, whose commercial director of Ireland Andrew Cowan took over as country director of the company's GB business.
Pernod refused to comment on whether the search for de Mardt's replacement would include external candidates and said the successor would be announced shortly.
Pernod Ricard UK deputy MD Simon Thomas said: "During this transition period, Laurent Lacassagne, chairman and chief executive of Pernod Ricard Europe, will assume the leadership of Pernod Ricard UK with the support of the UK management committee members, who will report directly to him."