Amazon has a conveniently timed treat for those expecting a 4K television under the tree this Christmas - it's now streaming movies in the Ultra HD resolution in the UK. Amazon switched on 4K streaming in the US a few weeks ago, but has now quietly added it in the UK, too.

This is very much a soft launch, however. It's only available through apps on Sony Ultra HD smart TVs, with further models from LG and Samsung due to be added next year. However, unlike rival Netflix, Amazon isn't currently charging any extra to receive streams at the higher resolution.

The company will offer 4K content to both Amazon Prime customers and those making standalone movie purchases. Titles including Captain Philips and Crouching Tiger Hidden Dragon are available in Ultra HD, but will set viewers back £14.99 a pop. Amazon will also be streaming its growing library of in-house productions in 4K.

Video streaming rival Netflix already offers 4K streaming in the UK, although customers have to upgrade to a top-tier subscription to receive the Ultra HD streams, costing £8.99 per month instead of the regular £5.99. Such streams also require a fibre/cable broadband service, with Netflix recommending a connection speed of at least 25Mbits/sec to stream the 4K content. As with Amazon, Netflix only supports 4K streaming on a limited selection of TV models - you cannot access 4K streams via a web browser or device such as the Apple TV or games consoles.

4K is the next big hope for the television/entertainment industry, after 3D once again failed to capture a mainstream audience. The capability to deliver 4K streams could give internet services such as Amazon and Netflix an advantage over conventional broadcasters, who don't yet have the bandwidth or receiving equipment to deliver "live" 4K television into our living rooms. Sky was reportedly engaged in trials of 4K broadcasts earlier this year, but has yet to announce a set-top box capable of delivering Ultra HD.