Checking whether public buildings have RAAC in them would have been the responsibility of every government since at least the time the material stopped being used in the mid 1990s.
Devolution was in place in Wales and Scotland by 1999, not long after discontinuation of the use of RAA, and since then Labour has been in power in Wales and the SNP in Scotland.
All governments have neglected this issue.
And it has been known about for a long time. A construction trade website says "In 1982, production of RAAC in the UK stopped amid concerns over its structural performance and life expectancy, which was subsequently predicted by BRE to be around 30 years."