Prospect and PCS members in the three agencies are angry that their pay and conditions are falling further and further behind as Defra seeks to make running cost savings at their expense. The action will begin at noon on Friday when staff will walk out to attend protest meetings at:

• the Central Science Laboratory (CSL) in York
• the Lowestoft, Weymouth and Burnham laboratories of the Centre for Environment, Fisheries and Aquaculture Science (CEFAS)
• the Rural Payments Agency (RPA), which has offices around the UK.

Defra itself negotiated a 5.85% increase for 2004. But at CEFAS, members have rejected a 2.7% offer; at CSL, a 3.49% offer has been rejected because it made no allowance for progression; and members at RPA are being balloted to reject an initial offer.

Prospect negotiator Fiona Sloman said: "These are dedicated staff who provide vital support to the agriculture industry yet they can receive up to £7,000 less than colleagues working in Whitehall on work graded as equivalent.

"Only four years ago all the agency and core-Defra staff worked for the same employer (MAFF) and had the same rates of pay. By treating its agency staff as second-class citizens Defra is destroying teamwork and wrecking morale. Increasing amounts of awards are being diverted out of basic pay and into performance pay. Half of every increase is unconsolidated. And pay offers are always many months late."

As pay rises fall further behind, agency members are being forced to rely on overtime and allowances to make ends meet. For example, one CEFAS marine scientist with post-graduate qualifications and six years experience in post receives just £17,500, while the majority of staff within the agency fall into the bottom half of their pay band.

Staff will be sending protest postcards to Defra Secretary of State Margaret Beckett and permanent secretary Sir Brian Bender. Further strikes and action short of a strike are planned.