I saw either one of these, or a Hen Harrier(female if it was one of the latter since the males are a different colour) the other day while fishing and it's rare you do see them. There is the trough of bowland near by, which is home to Hen Harriers and in the other direction, an RSPB nature preserve, where there are families of Marsh Harriers visiting there every summer, so it could have been either.
Hen Harriers, just like Peregrine Falcons, are often killed by your rich Gamekeepers on the moors as Hen Harriers and Peregrines from time to time may take a grouse, so grouse hunters shoot them, trap them, crush their eggs, kill their young, etc and nothing can really be done as these moors are owned by these rich gamekeepers, who when caught killing birds of prey, are often only given fines, which is fuck all to them. They should start giving cunts like this serious jail time, or better yet just release their names, addresses and pictures online so that 'vigilantes' can give them a good kicking.
The other ones are those clowns who race Pigeons. These are less likely to kill Harriers, but do kill Peregrines and Sparrowhawks, due to the obvious, they like eating Pigeons, although if you're to partake in a hobby like that, then it's part and parcel of it. You can't just go around killing everything for your own personal gain. You don't see my going out killing Otters, Herons, Kingfishers, Grebes, etc because they eat fish and I enjoy going fishing. One of the positives to going fishing is that you see these animals and get to pretty much live with them temporarily in their environment.