The law was changed to permit jamming in prisons. It is quite difficult to implement because you have to avoid jamming outside the prison, but a successful feasibility study was carried out. And the government decided it was too expensive to roll out nationally.

Yes, it is.

https://www.ofcom.org.uk/spectrum/interference-enforcement/s...

Criminal, according to Ofcom regulations.

https://www.ofcom.org.uk/spectrum/interference-enforcement/s...

There are after all good reasons to ban them, but even if those reasons didn’t exist, the Tories would ban them for their usual “law and order” reasons.