In December 2011, Microsoft announced it would start IE so that users ran the newest version suitable for their copy of Windows.

Under the plan, Windows XP users still on IE6 or IE7 would be updated to IE8, while Windows Vista or Windows 7 users running IE7 or IE8 would be pushed to IE9.

Previously, Microsoft has always asked users for their permission before upgrading IE from one version to the next, even if Windows' automatic updates was enabled.

First to get the automatic treatment, Microsoft said, would be Australia and Brazil, both guinea pigs for the January 2012 debut. The program would then be gradually expanded to other markets.

Yesterday, Microsoft declined to disclose what other countries, if any, had had the auto-upgrade switched on.