Wanderoo:
The Met. Office had and has
Procedures And Communications in the event of a release of Radioactive Material (PACRAM)
My generation of C and P Met Os [we reached that level c. 1980] certainly took our regional responsibility seriously and undertook no-notice exercises with Police and Fire services.
Before that, I rather think the procedures and algorithms were "kept in a box file in the cupboard". The first no-notice I provoked at Cardiff Weather Centre caused a lot of fluttering and sqawking!