Could drone delivery ever be commercially viable?

What would it be like to buy something on your computer and it appearing at your home just 30 minutes later?

Online retailer Amazon says it wants to make that a reality.

The company is testing unmanned drones or Octocopters, which could deliver packages weighing up to 2.3kg to customers within half an hour of the order being placed.

Amazon says it could take five years for the service to start.

Nigel Cassidy reports.

Video provided by Amazon.