Google has launched its first tablet computer in San Francisco.

The Nexus 7 is the internet giant's attempt to catch up to Apple and Amazon in the tablet market.

It has been designed specifically for Google Play, the online store that sells movies, music, books, applications, and other content.

But Google Play has come under fire from critics for not holding as much content as Apple's online shop.

The debut of the long-anticipated tablet computer bearing Google's brand and equipped with its latest operating software kicked off an annual conference for about 6-thousand computer programmers.

With a screen measuring almost 7 inches diagonally and a 1280x800 HD screen resolution, the Nexus 7 is seen as a direct challenge to Amazon's Kindle Fire.

The tablet could also appeal to consumers looking for a less expensive, less sophisticated alternative to Apple's iPad.

Google's Nexus 7 will be available from mid-July for £160.