@Spudlet it does seem to have improved. My mum lives in the Welsh mountains and they have a similar problem there. They don't seem to manage the mountain like we do in the forest so they have all sorts chucked out on the mountains. In mum's area it's mostly coloured cobs but a few people put their rugged up Thoroughbreds out and bring them back in at night!
The farmers seem to run it amongst themselves but because no one oversees it ponies are dumped all the time.
@FieldOfFlameAndHeather Iceland's rules are mostly to protect their native horses from diseases that they don't have, rather than breed purity.
However the Dartmoor/Dartmoor Hill situation was a lot about breed purity because unfortunately the Dartmoor Hill ponies were any old mish mash of breeding/in bred which meant they had poor health, no use, and were of no monetary value, therefore meaning they were dumped and neglected.
In comparison pure bred Dartmoor ponies have had generations of breeders developing the breed, are very much sought after, and worth a fair bit of money.
I'm not saying people don't ever abuse pure bred animals but surely it's better to have an animal which is healthy, has a use, and a value/there is a market for them?
It's the same with dogs. People want pure bred kennel club breeds or "designer mongrels". The Heinz 57s get left in rescue centres.