Windows 9 will be announced under the codename Threshold at the BUILD 2014 conference in San Franciso this April, Windows blogger Paul Thurrott has revealed.

Sources have told Thurrott that Windows 9 will see the return of the Start Menu, with the ability to run Metro-style apps on the desktop alongside your regular desktop applications.

Windows 9 will be released in April 2015, approximately one year after its announcement.

BUILD 2014 takes place April 2-4.

Windows 8 looks set to become the next Windows Vista, with Microsoft hoping Windows 9 will prove just as popular as Windows 7.