Here we go....
Spearfishing is live and active in the UK and I can assure you it needs dedicated people to do it. i.e. no vis and cold. Portland Bill is a great place to dive, very deep, and when the tide sweeps you off the west side getting into the calm water on the east side was always a challenge
Most people who frown on spearfishing tend to come from diving clubs who are told that spearfishing kills every fish in the sea. An average trawler will take 100 times more fish on a trip than the whole of UK spear-fisherman in a single year. Every fish I shot was eaten and fresh fish,i.e. not several weeks old by the time it gets to the fish counter.
Spearfishing is the only form of selective fishing.
During a competition only fish that can be eaten, i.e. no Wrasse, and that meet a minimum weight, i.e. are of a breading age, can be weighed in. For sure some fish are underweight but I'm amazed that the fish counter at Asda has fish which are much smaller than any diver would take.
For myself I did it because I could dive for 6 hours at a time whereas there was to much organisation and messing around with aqua-lung diving. When I was fit I could manage 35m but that was some time ago. Plus I was a rubbish spear-fisherman but loved being underwater. The problem was the boats started to get bigger ( so did I ) and I stopped getting out of them.
Not sure there are any other spear-fisherman on here but you probably know about http://www.underwaterfishing.co.uk/
Looking to get back in the water this year.