Strike negotiations may be used to prevent National Grid walkouts
Two unions have already written to National Grid's chief executive regarding possible industrial action.
National Grid managers may find themselves locked in strike negotiations as it faces the prospect of a winter of discontent from its staff over pay.
The company faces the prospect of a quarter of its 10,500 employees taking industrial action in January, which is the coldest month of the year historically, the Independent reports.
Unite is expected to write a letter to chief executive of National Grid Steve Holliday next week, while Union and Prospect have already done so and warned that a ballot of the creation of picket lines will take place within the coming days.
Workers at the company, which has a poor recent record in terms of industrial relations, have been offered a 7.2 per cent pay rise over the next three years.
"Our members are disappointed with the company's attitude towards them," said Union's head of business Mike Jeram.
"They have worked hard in difficult weather conditions to deliver good profits and don't feel they are being fairly treated," he added.
Last week, journalists working in Newsquest offices across the country were considering strike action as a result of proposed job cuts and pay freezes.