Microsoft has revealed that the discovery of content featuring "partial nudity" was the reason the Windows Vista version of Halo 2 was delayed.

In a statement issued this morning the company said, "It has come to our attention that an unfortunate, obscure content error which includes partial nudity was included in our initial production of Halo 2 for Windows Vista.

"As such, we have updated the initial game packaging at retailers with a label, so customers are aware before purchasing the game... This packaging will only be labelled for the initial run of games; subsequent shipments will not include the content."

The company has also released an online update, available from Halo2.com, which consumers can download in order to remove the content in question.

The Vista version of Halo 2 was originally due to launch on May 8 in the US and May 18 in Europe. However, the dates slipped twice and the game is now due out on May 31 in the States and June 8 in Europe.

Microsoft is doubtless keen to avoid a repeat of the 2005 'Hot Coffee' controversy, where a hidden mini-game which featured the main character having sex was discovered in Grand Theft Auto: San Andreas. A series of investigations and lawsuits followed, and the game was re-rated as being suitable for 'Adults Only' by the ESRB.

Microsoft's statement concludes, "We apologise for any inconvenience this may cause our customers. At Microsoft we take the Entertainment Software Ratings Board guidelines very seriously and hold ourselves to high standards, with our customers always in mind."