THE first live television broadcasts to UK mobile phones started this week as Channel 4 beamed pictures of its controversial new round- the-clock sleep-deprivation show Shattered to phone users around the country.

Though the test service has been largely unheralded, experts believe the technology could spark a resurgence in the telecoms and media sectors and open up a 550,000-ayear market.

Pictures are being beamed to GPRS or 2.5G phones capable of taking video feeds at a cost of 1 per day. The use of the current crop of phones for the broadcasts is expected to pave the way for the more powerful 3G models when they become popular.

The service is a collaboration between programme makers Endemol UK, Channel 4's interactive arm 4interactive and wireless streaming company Vemotion, a spinout of BT Exact. The show features a dozen individuals trying to stay awake for a week to win 100,000.

Tony Antoniou, chief executive of Vemotion, said: "The service went live on Sunday and it's working a treat." His firm has an agreement with Channel 4 to provide a similar service for other reality TV shows over the next year.

"In a sense this was a trial, but it will be promoted as a service on the next series of programmes. It runs beautifully on 2.5G which is a real triumph for the UK because it uses a compression technology called H264 developed by BT."

Vemotion is working on a system for in-car broadcasting and separate applications for use by the military and emergency services.

Analysts say sports events, soaps and audience-participation shows are the most likely entertainment applications.

"There is a huge potential," says Paolo Pescatori, mobile TV analyst for market researcher IDC, which has tested services involving sport and news.

"Our last estimates put potential customers at 26.7 million in Western Europe and five million in the UK by 2007."

Markus Leikola, a consultant for Nokia, which is due shortly to announce its own system, says: "I think we will see content that will have high user value - a clip of a must-see event or area-based information that may have tourism value for example.."