"We were told it was getting pressure to cut costs from financiers backing the new plant," said Amicus GPMS East of England branch secretary Vernon Robson.

"We now fully expect NJP to announce that it's got the finances and to choose which site it's going to use so as to end everyone's uncertainty about the future," added Robson.

Robson has estimated that the cost-cutting measures should save NJP around 2m a year.

NJP was unavailable for comment.