Market analyst Canalys reports that 1.6M fitness bands and smartwatches combined were sold in the second half of last year, and is predicting that more than 17M devices will be sold this year, driven largely by forecast sales of 8M smartwatches.

Morgan Stanley analyst Katy Huberty recently forecast that the iWatch could generate $17.5 billion in the first twelve months.

We’ve recently run a series of pieces about what is known about the iWatch project so far. iOS 8 appears to be gearing up for a major focus on fitness and health, presumably with the iWatch in mind. Recent Apple hires include a sleep researcher and physiologists, with a large and high-calibre team believed to be working on the project.

It appears likely that the iWatch is intended as an iPhone accessory rather than a standalone device, with data from it accessed via a new Healthbook app.