INDUSTRIAL action could black out TV screens and leave emergency services facing a communications crisis as broadcast workers launch a dispute over pay and conditions.

Workers at NTL's broadcasting arm are planning an indefinite overtime ban in a protest over pay.

The action could wipe out ITV, Channel 4 and Channel 5 from North-East TV screens, although the BBC is not affected.

More seriously, the ban could also have a serious impact on radio communications used by the emergency services.

In the North-East, NTL engineers are responsible for the communications systems used by the coastguard.

Police chiefs in other parts of the country, including the Metropolitan Police, were last night putting contingency plans in place to ensure their radio communications are not affected.

North Durham MP Kevan Jones said he hoped the emergency services would have fool-proof back-up plans.

The industrial action is due to begin on Wednesday and to continue indefinitely.

Last night, NTL said it had informed customers, particularly in the emergency services, of any disruption and said it had contingency procedures.

If Pontop Pike and Bilsdale mast television and radio transmitters in the North-East break down, NTL engineers and technicians taking part in industrial action will refuse to fix them out of hours.

That means if ITV, Channel 4 and Channel Five services experience problems they may not be fixed until the following day during normal working hours.

NTL could face thousands of pounds worth of fines if services break down.

Workers at NTL's broadcasting arm, which supplies emergency services communications, all terrestrial television except the BBC, some digital services and commercial radio stations, have launched action with union Bectu to protest over new pay and conditions terms.

Negotiations between Bec-tu and NTL, which have rumbled on for a year, broke down recently.

David Beevers, national Bectu official, told The Northern Echo: "We will be refusing to work overtime in protest at terms and conditions.

"Radio and TV, including some digital, could be affected, as well as the coastguard, other emergency services around the country, and the RNLI.

"The communications arm of the Met Police will also be affected. Basically, if there is a fault, we will refuse to fix it out of hours.

"Any break in communications would not necessarily be life-threatening, but it increases the risk."

Although NTL said it could not confirm how many workers were taking part in the strike, a spokeswoman said more than 70 per cent had already signed their new terms and conditions.

It said the Metropolitan Police were aware of the problems, but a Met spokesman last night said he believed communications would not be affected, despite Bectu saying they would be.

Mr Beevers assured the public that if there was a terrorist strike or a similar disaster, industrial action would be suspended.