Google has announced its latest smartphone, the Nexus 5, thereby ending weeks of speculation and leaks.

The new handset, which is being billed as “the slimmest and fastest” Nexus yet, features a full five-inch HD display and a 2.3GHz Snapdragon 800 processor.  Two models will be released, one with 16GB of memory and the other with 32GB.

As part of the Nexus 5 announcement, Google also showed off the latest version of its Android operating system: KitKat.

The new operating system seemed to offer a number of refinements and new features, with perhaps the most compelling being OK Google – a new voice-activated feature that allows users to carry out a number of different activities, such as playing music, texting and searching the web, without touching the screen.

Other new additions include the Immersive mode, in which games and movies take up the whole screen with navigation buttons and icons being hidden.

The new KitKat system is believed to be less memory intensive than its predecessor, Jelly Bean; indeed, Google has claimed that it is capable of running on devices that only have 512MB of RAM.  This is doubtless a move to ensure that its features work effectively on the large number of lower-level smartphones that are becoming more popular in some markets.

Last month Google chief Larry Page made the claim that 1.5 million Android devices are activated every day.  The platform claimed to have an 81.3% share of the market in the third quarter of this year, shipping 204.4 million handsets compared to the 33.8 million iPhones purchased in the same period.