Dai Hudd, Assistant General Secretary of Prospect, the specialists’ union, said multi-year settlements had attractions but the reaction of unions would depend on the actual increases envisaged.

He said: "We have never accepted the argument that public service pay has been or is the cause of inflation.

"Last autumn civil service unions gave the Chancellor an independent report which refuted the government’s claims on pay and to which they promised to reply. They never have. That’s no surprise as it exposed the complete lack of evidence for their pay policy."

Hudd added: "If the new policy is merely the 2% policy repackaged over three years it will continue to lead to increasing conflict among public servants. If that’s all it is, it’s just not good enough."

Prospect represents 35,000 scientists, engineers and other specialists in civil service agencies and non-departmental public bodies.