By Alfred Hermida BBC News Online technology editor

Sky will remain the dominate player in the on-demand market

By 2008, more than 15 million UK homes will have access to some form of on-demand programming, media analyst Screen Digest has predicted.

This is up from 10 million households at the moment.

On-demand movies, via digital TV and on services such as Sky, will remain the most popular choice, though broadband will increasingly play a bigger role.

"Movies are central to the mix," said Screen Digest's Dr Guy Bisson. "TV programmes are becoming increasingly important but still make up a small part of the cake."

Money talks

Currently there is only a limited availability of true video on-demand in the UK.

Most services either by satellite or cable broadcast films at staggered intervals, but there is increasing availability of movies which can be watched when the viewer chooses.

The modern TV home is increasingly complex both in terms of the consumer and multiple technologies leading to multiple choices Dr Guy Bisson, Screen Digest

These can be either part of a subscription package or pay-per-view, costing around �3.50.

According to media analysts Screen Digest, there are currently just over 10 million homes in the UK with access to on-demand services, accounting for 40% of households.

In financial terms, viewers will have spent �141m this year on on-demand films and shows.

Screen Digest expects this to almost double to �268m by 2008, with 60% of homes being able to watch on-demand shows.

"The modern TV home is increasingly complex both in terms of the consumer and multiple technologies leading to multiple choices," Dr Bisson told a video on-demand seminar in London.

I want my net TV

One emerging technology is IPTV - sending broadcasts to a TV set via broadband. Once such provider is Home Choice, and several telecoms companies such as BT are planning such services, but it is still early days.

"Sky will still control the lion's share of the on-demand market," said Dr Bisson. The satellite broadcaster will account for 60% of the on-demand market in 2008, with IPTV making up just 6%.

Across Europe, some 30 telcos and network operators are testing IPTV services. Screen Digest estimates that 4.5 million homes in Europe will have internet TV services by 2008.

"The reality is that those services that have been trialled and are going commercial are not having the easiest of times in an aggressive pay TV market," said Screen Digest analyst Arash Amel.