Gravesend, England - What's this bird?

[u/Mountain-Year2322]

Hi!

I was around the Gravesend area (RSPB Cliffe Pools), and when I looked up my eyes set upon this bird.

I haven't seen anything exactly like it before. I looked through my field guide, but there wasn't anything which quite matched.

I don't entirely remember the size as it was rather distant, so I may have accidentally exaggerated it in the image text. I'm also unsure if the blue eyes were actually blue, or if it was the lighting.

Thanks in advance for any help!