How many?
Bear in mind that ham operators worldwide generally have access to small bits of spectrum scattered all over the bands, squeezed between the other legitimate users of those bands. Anything which interferes with ham radio has the potential to interfere with everything else, which includes leisure services like TV & FM radio, emergency services, and other professional users.
It's Ofcom's job to ensure fair treatment for *all* users, which of course it hasn't done since it was turned into the government's spectrum pimp.
As with any other law, once the people charged with enforcing it sell out, lots of other unscrupulous folks will jump on the bandwagon and start abusing it because they know they won't be censured. Just because ham users are in a minority doesn't mean that their concerns can be ignored. That way lies tyranny, or anarchy.