A staff member said: "At a time when people are fearful for their jobs and future, staff are being told they are not allowed to consult with professional independent advisers on RHS property. The RHS is calling it an open and transparent procedure, while hiring in external HR advisers."

Along with looking to save 10 per cent on the wage bill, a two-stage restructuring process is underway.

An RHS representative said: "The RHS is under no obligation to make our premises available for meetings with Prospect. Any employee is, of course, perfectly entitled to speak or meet with Prospect or any other trade union at an appropriate time and place."