Microsoft's long-awaited Surface event invites journalists to join them for a "small gathering" later today from 4pm GMT (8am PT, 11am EST) to 6pm GMT (10am PT, 1PM EST). The wording of the invite points to a smaller tablet, an additional form factor to compete with Apple's iPad Mini.

It should lay to rest speculation around what could be Microsoft's first pint-sized Surface, expected to be a note-taking device with a 7- or 8-inch display. Other specs are thin on the ground: the software giant previously confirmed it was working on Surface devices with "multiple aspect ratios and sizes".

Multiple sources recently tipped the Surface Mini to feature a 7.5-inch, 1440 x 1080 pixel-resolution display, which would lend it a 4:3 aspect ratio like Apple's iPad, rather than the 16:9 worn by previous Surface devices.

Full-fat Windows?

The killer question is whether Microsoft will plump for the comparatively limited Windows RT 8.1 over the fuller featured but more power-hungry Windows 8.1. Rumours point to the inclusion of an ARM or Qualcomm processor, which means it would run RT.

That said, with a slew of well-received, smaller Windows 8.1 tablets outed in the past year - including the Lenovo Miix 2, Acer Iconia W4 and Dell Venue 8 Pro - we wouldn't bet against Microsoft covering all bases to keep up with the competition.

How Microsoft is going to pitch a Windows RT tablet against an armada of sub-£200 Windows 8 tablets is going to be interesting exercise.