I have found iron phosphate granules, used in conjunction with various traps, to be the most effective in keeping their numbers down. Of course, I don't have to deal with them as often as people in wetter climates do!

it depends where I find them. when potting on plants all get squashed. in the borders most get collected and put at the bottom of the garden under the beech tree. this is where the local thrush has an anvil, there has been a pair this year and reared 2 babies. many of the birds poke around there as that is where I tend to put food out for them. Then very occasionally I use sluggo [ferric pellets] as this stops them feeding and they burrow into the soil. this is in the middle phase of a large hosta grows.
I have resident hedgehogs too and they clearly help keep the population down.

Frogs! Hedgehogs! I have a wildlife pond. It isn't beautiful but it is full of frogs and I'm sure that's why I find very few slugs in my garden. There must be some, however, as my hostas have suffered a bit.
I haven't been lucky enough to see a hedgehog in the garden this year although I have areas suitable and dishes of water about and I have used rigid plastic net to make ladders all around the pond for them to climb out if they fall in. I tried melon skins but only found lots of woodlice in them, so I think the frogs must be doing a good job.

Been known to go out on slug & snail hunt with torch & bucket @ 10 at night! Didn’t have many at start of summer but with the rain we’ve been having they’ve exploded! I put them in my green bin to be ‘recycled’. Am amazed by the size of some slugs! Never seen them this big, biggest one measured 6 “ or 15 cm!! 🐌 Am sure I do not get them all so wildlfe get a fair share as well. My garden is a mature garden and lots of bounderies are covered in ivy which is the ideal hiding place for them.

Strangely I have seen very few this year - no hedgehogs (badgers around), only seen one frog but am wondering if the slow worms are to be thanked. Not very helpful, sorry.

Blue slug pellets. I know, I know, but they work for me

I haven't had anywhere near as many this year so maybe that frog helped. I know a man who collects them in a bowl/bucket and takes them to the nearby grassy/woody/park area which doesn't have any flowers.

The robins & mockingbirds in my garden tussle over slugs, worms & snalls. They are all fair game, but I hardly see any at all. Then they sing me the sweetest song I ever heard. It's beautiful.

Around pots copper tape is brilliant and my dahlias are untouched. They now sell it at Poundland but it's too narrow so I double it up. The little demons seem to be able to 'jump' the half inch of that tape. More expensive tape is wide enough to deter.
Copper rings are useful for young plants in beds or pots but surrounding plants need to be trimmed or slugs will find a way. Certainly, the rings are useless once the plant grows away.
We do have hedgehog(s) but their diet contains only 5% slugs. What I really need is a pond and frogs.
I would never ever use blue slug pellets because of the risk to wildlife and for the same reason would never use pesticides or any weedkillers and haven't done for 20 years.
It's worthwhile going out at 10pm and hand-removing slugs and snails.. they go in the compost bin where they can be happy. I'm never sure what to do with snails as they cannot get out of the compost bin? They do manage to get in there though so perhaps they can get out too.
Sheep wool is also effective but nothing is perfect.

For containers, not only use copper tape around the outside, but put some mesh in the bottom of the pot so they don't get in that way.

I’m using ferric phosphate pellets. They work fine.

The metaldehyde type will likely be banned next year anyway.
I've often read that the larger slugs aren't really a problem as they mostly eat decaying matter but I've never really seen an authoritative breakdown of the information, that might be helpful though how you'd target the main offenders??

http://www.slugwatch.co.uk/

Having looked up ferric phosphate thinking I could use it too, I quickly realised that it is not something I would even consider because of the risk to wildlife. Not just slugs either. Look it up and make your own assessment. It always depends on what you want to do about slugs. Do you want to deter them or kill them? Other wildlife might also suffer and is it worth the risk?

A link or two might help Merlin. There's a bloody lot of internet out there?

It seems that iron phosphate by itself is little danger to the environment, but some brands also contain EDTA, to make them more rapidly effective. EDTA is somewhat more toxic to wildlife and earthworms.
Check: https://www.gardenmyths.com/slug-bait-metaldehyde-iron-phosphate/
....Which reminds me, I need to check the label of the brand that I have on the shelf, at work!

Thanks Tugbrethil, good to know