HP has announced the Slate21, a bumper-sized Android tablet that can fold to stand like a desktop PC. Running on Android 4.2.2, it's one of the first significant forays by HP into the world of Android.

The device uses Nvidia's ultra powerful Tegra 4 processor which was announced at CES earlier this year. Complete Android certification means you get the full suite of Android apps to enjoy, all at 1080p on its 21.5-inch screen.

HP's Eric Wiggins said, "Honestly, that larger screen allows for a better shared experience. This could replace one or two mobile devices in your home that could be used as a shared device for the house. Creating a large-screened device with touch functionality, we thought we could unlock more uses."

HP's tablet failings with the likes of WebOS mean the company is rapidly scrambling to play catch-up with the rest of the Android competition. Launched this year was the Slate 7, a dual-core tablet running Jelly Bean.

This new 21.5-inch device is more a crossover between HP's traditional strengths in the desktop market and the world of Android. It represents a departure from Windows 8 and towards Android as an operating system. If it takes off, expect to see more of the same from HP and smaller smiles coming from Microsoft as Windows 8's tablet offering fails.

Staggeringly, the Slate21 will launch in the US for under $400 - a fraction more than £260.