It has come to my attention that Jeremy Corbyn is now promoting the idea of a "British Digital Corporation". This mostly seems like a bad idea to me and I'm in favor if keeping the government out of my internets as far as is practically possible. Having a nationalized version of something like Facebook would be really bad for privacy, because when the government knows the contents of your private life then this doesn't usually go well. In the last century using far less sophisticated equipment governments used knowledge of people's private beliefs against them in terrible ways and it would not be a good idea to repeat that.
Also there's currently a lot of interest in regulating the internet, but I think we should be really cautious about this. Many privacy-centric people approve of the European GDPR, but regulation cuts both ways. One day it might be in your favor and the next it might not. We already know that governments tend to intensely dislike encryption and want to spy on their citizens as much as possible. After Snowden there was no rollback of government surveillance powers - quite the opposite.
If a hypothetical near future Corbyn government were to try to improve the condition of the internet with some sort of decentralization programme then what should it do?
The first thing is incredibly easy: fund free software development and have a policy that any software created or supplied for government use must be under a Free Software license. No more proprietary lock-in.
Instead of a "British Digital Corporation" make something like a "Free Technology Fund" and divert whatever money would have been spent on proprietary software or SaaS subscriptions into it.
Designate some of the radio spectrum to be used for public internet provision. A sort of "citizens band" but for internet data. That will enable long distance wifi on a band which doesn't require individual licenses.
Regulate the ISPs to supply municipal mesh networks to every city. Some percentage of any new infrastructure must be municipal mesh. Once a significant number of people start to realize how much public mesh networks chould change the communications landscape then I think there would be a big "aha moment" and a whole new phase of technology development.
Regulate in favor of encryption. That citizens have an inalienable right to communications privacy if that's what they wish to do. Make it illegal for the government to interfere with private digital communications (aka "equipment interference").
Regulate that internet routers supplied by ISPs must at a minimum be able to run some number of internet services. Things like an xmpp server or cloud server such as NextCloud. That's well within the capabilities of current technology and would greatly assist with decentralization of services.