Computer industry analyst Dataquest has revised downward its forecast of sales of the Microsoft Windows 95 computer operating system, it announced yesterday.

The forecasting firm expects sales of Windows 95 to reach 45.7 million in 1996, 27 per cent fewer than an estimate made earlier in the year.

The drop in estimated sales is due to the unexpected continuing success of Windows 3.1 which Windows 95 was designed to replace.

One analyst, Mr Chris Le Coq, said that large and middle sized firms are fuelling the demand for Windows 3.1 while anticipating the new version of Windows NT for Workstations.