The decision to refer the relocation plans to the Scottish Parliament’s finance committee was announced on 1 October after SNH unions presented evidence to the public petitions committee.

Addressing the committee, Prospect and PCS negotiators questioned the sense of the move that will cost in excess of £30m - £10m more than originally anticipated - and result in the loss of an estimated 200 highly-skilled and experienced staff.

In their statements the unions highlighted how SNH’s own board do not believe the proposals represent value for money, that the environment agency’s new headquarters are likely to be built on a greenfield site and the proposals do not meet the Executive’s own relocation policy criteria.

Speaking after the meeting Prospect negotiator Alan Denney said: "We firmly believe that all parts of Scotland should benefit from the dispersal of public sector jobs, but at a cost of over £100,000 per job, we must be absolutely sure that it is done properly.

"For the dispersal policy to work it must be based on staff being persuaded to move, not forced by the threat of losing their jobs. SNH must improve not reduce the quality of the services provided and in a way that balances costs with genuine benefits."

The unions were invited before the committee after submitting a petition to the Scottish Parliament signed by MSPs from all parties.