Is this a sparrowhawk or peregrine (or something else?)

Hello, whilst on my way to work, I saw a dark grey/blue bird of prey in a tree on the road. I didn’t get to see much of it, but it was pretty dark and around a large pigeon size. This immediately made me think it was a peregrine but I’m unsure if it was. I also know that sparrowhawks can look dark, so it’s between these two. I know there’s not much but I’ll list everything so someone can help decide. I know there’s definitely both in my area. 

Location: Outskirts of village on border of field. Perching in medium sized tree next to road. Around 8:30AM

Colour: Dark grey/blue slate colour, couldn’t see much else 

Size: Large pigeon or small duck 

Any ideas are appreciated,

Thanks, Ellis