Catherine Donaldson, vice-chair of the union’s Defra branch, said:“In the current environment, staff will be suspicious that this change has more to do with cost-cutting than service delivery. This must not become an excuse to reduce the numbers of veterinary officers, animal health officers or scientists whose work is so vital in the lab and in the field.

“These are the very people who are the frontline of the fight against dangerous animal diseases like foot and mouth disease, bird flu and bovine tuberculosis.”

Donaldson said the Veterinary Laboratories Agency and Animal Health used to be one unit “so this move will return the two agencies to where they were 15 years ago.”

VLA, which is based at Weybridge, Surrey, employs 1,280 staff. Animal Health, based at Worcester, employs 1,560 staff.