The action reflects the anger and frustration felt among ONS staff who, four months into 2004, are still fighting an imposed pay deal for 2003 which is among the worst for any group of public servants.

Prospect negotiator Rose Willis said: "Management at the UK’s official statistical service have ignored its own figures which show that this pay deal is not only among the lowest in the public sector but discriminatory on five counts including sex and race."

The management deal will:

• introduce secretive pay bonuses outside the agreed pay scale
• impose a miserly (£400) annual increase for the lowest paid staff
• allow pay for key specialist workers to fall thousands of pounds behind equivalent jobs outside
• impose a 1% increase on its most experienced staff.

In addition to the demoralising pay offer, ONS staff face added uncertainty after management announced two weeks ago that it plans to relocate 1,100 jobs from the Titchfield site in Southampton, and 600 from the London headquarters, to Wales or the South West. There is no evidence that this will benefit taxpayers. The Newport site also faces the threat of closure. The announcement coincided with the opening of a £750,000 major refit at the Titchfield office.

Said Willis: "By imposing a discriminatory pay deal and then announcing plans for widespread job losses without any staff consultation ONS management have behaved in an unbelievably arrogant and contemptuous manner.

"They seem comfortable wasting money on a new office, including chairs priced at £400 each, which is likely to be bulldozed if the relocation plans go ahead. But they cannot see fit to listen to their most valuable asset, their staff, and provide them with a living wage. It is any wonder that staff feel they have been forced into taking this action?"

The unions want ONS to withdraw the new secret bonus scheme, suspend performance pay for 2004 and use the money in the bonus pot to fund a decent increase for staff on the lowest pay. And they have warned that longer-term faults in the pay system also need to be rectified if the government’s statistical service is to retain its skills and knowledge base.