Car for sale at the Side of the road

[djt100]

Can anyone offer any advice on who to report these to, the main road near me that has plenty of free parking on has started to sprout these piles of cack for sale at the side of the road, I have read before that this is illegal for traders, But who do you report it to ?

There are about 10 in the space of a couple of hundred yards so I don’t think these are private sales.