On behalf of 500 plus members in the organisation, the union has protested to EH management that it is breaking agreements to put in place recruitment bans or try to deploy staff earmarked for redundancy into alternative posts. Other measures designed to avoid or minimise redundancies are equally not being followed.

The union has been kept at arms length from the process and has not been properly consulted. A minimum of 50 frontline posts face the axe under EH’s Coming of Age Modernisation programme.

The move is the latest in an ongoing row over pay and job losses at the heritage body, which has already seen staff snub an invitation from the chief executive to a fancy dress party in Blackpool, as they feel the money would be better spent honouring previous agreements on pay and pay progression.

Prospect negotiator Phil Carpenter said: "Management seem to be sending out a very mixed message. They imposed a poor pay deal last year, and have indicated that worse is to come this year, yet they are happy to pay for the entire workforce to attend a two-day party to mark the organisation’s 21st birthday. Our members are being asked to celebrate while they and their colleagues face the sack.

"All we are asking is for management to follow their own procedures and take notice of what we say, as we are the legitimate and recognised voice of staff. We also know that many external partners of EH are unhappy with what they are doing and the way they are treating their staff."

The union is seeking a meeting with English Heritage management, before new pay talks due to begin within a fortnight, to try to seek agreement over the proper implementation of the redundancy procedures.