Bumpy start for the Blackberry Playbook?

A year after Blackberry first spoke of a tablet computer, the Playbook finally goes on sale in North America.

The 7 inch gadget is smaller than the market's dominant device, the iPad, and has also suffered worse reviews.

Blackberry's maker has already said development costs will weigh on profits which has added to a share price slump.

Caroline Hepker reports.