Referencing the board’s independence, it urges them to disregard the recent Treasury guidance on pay which limits rises to 1-1.5%.

The letter outlines concerns about the agency staff’s ability to deliver its key objectives, highlighting the example of attracting nuclear specialists.

It says: “Salaries have fallen far below the level needed to attract, and there needs to be a substantial increase to recruit and retain effectively”. 

The board are advised “the Agency floats on a sea of staff goodwill” and that a recent survey found that half of union members are working more hours than they are paid for.

“Levels of payment to be on stand-by to respond to emergency have fallen well below prevailing levels among Category 1 responders, and the Agency struggles to fill the rotas - which are staffed on a voluntary basis out of hours - to make sure it is properly placed to respond.”

Prospect negotiations officer Kevin Warden said: “This patient committed workforce has limits, and another real term pay cut this year, on top of around 15% real terms loss as a result of the pay cap,  would test these.”