Viewers are fleeing traditional TV in record numbers in favour of streaming TV shows, according to a new report by US company Knowledge Networks.

It found that more than one in five (21 per cent) Internet users aged between 13 to 54 now accesses streaming video to watch full episodes of TV programmes - up from 10 per cent in 2006.

Most IPTV is on demand viewing direct from the networks, although the popularity of third party sites like the excellent Hulu has doubled too - now accounting for nearly a third of all TV shows watched online.

Web TV killed the video star

The figures don't look so great for traditional TV watching but they hide some interesting facts. For instance, nearly 90 per cent of people say they watch TV online so that they can watch a current episode that they missed - implying that online TV is largely replacing VCR time-shifting.

However, 40 per cent also say that they like to catch up with the previous season or classic episodes, and 18 per cent use web TV to try out new shows they've heard about.

Interestingly, viewers are starting to look beyond their PCs when watching internet TV. Two-thirds (65 per cent) of streamers expect to be able to watch their favorite shows on the device of their choice.

This expectation reaches across generations, from 66 per cent of teens to 57 per cent of those 50 to 54.

It looks like web ads are getting better, too. Nearly two thirds of viewers said that watching whole episodes increases their consideration of sponsoring brands, compared to just over half in 2006.