Network Rail and train companies will hold urgent talks with rail union Aslef to try to avert a threat of action by drivers.

Thousands of train drivers had agreed to take indefinite action from Monday in a protest over safety levels that would have caused "chaos", Aslef said.

Members would refuse to pass through areas with a new communications system.

Aslef said Network Rail had previously refused to talks, but the company said it was an issue for train operators.

Action was threatened after long-running talks broke down, which centred on the ability of drivers to alert other train drivers and signal operators to an accident or other problem on the track.

Aslef said the Interim Voice Radio System (IVRS), introduced two years ago as a trial, had failed on a number of occasions.

The union had warned the action would cause "utter chaos" until the dispute was resolved to its satisfaction.

Much of the west coast mainline, and services from London to Manchester, would be among those hardest hit.

Aslef said it had instructed drivers to halt trains and refuse to pass through Stoke, south of Manchester, and Ledburn Junction, on the West Coast mainline in Bedfordshire.

Its members would also refuse to drive trains going through the Dorset Coast and Horsham, West Sussex, it said.

The union said this would involve "at a minimum" trains operated by Virgin, West Coast, Cross Country, Silverlink, Central Trains, Arriva trains Wales, Southern Trains, EWS, Freightliner and other freight operators.

After talks broke down on the IVRS system, Aslef's acting general secretary Keith Norman said: "We will not be party to putting lives at risk.

"I hope the public will not only understand, but support, action aimed at saving the lives of our members and the public."