A laudable aim that won't happen
Like others on here, I don't really believe this will happen.
I have some sympathy for having a standardised set of standards so data can pass from one system to another.
Big central govt will always be bespoke - unless we just want to buy the e-government model that Estonia will share (that would be far too sensible of course).
Local govt | police | NHS haven't standardised the important things that would allow competition.
This is often hampered by pernicious practice by IT providers who charge exorbitant fees for API keys to allow interactions between systems.
This prevents councils moving forward.
It could all be so much better, cheaper and more efficient.