Could be a leucistic greater spotted woodpecker (assuming you're in the UK) Leucism is a condition that affects colour pigmentation and melamine.
HOWEVER.... I'm only on my phone and my ID skills are ummm questionable
Too small for great spotted woodpecker and wrong proportions IMO. Can't suggest anything as colours washed out (not sure if it's the photo,the bird or both!). Proportions possibly siskin, but not sure.