Is this a white blackbird and are white blackbirds rare?


I wonder if anybody on here can assist me?

I've just joined RSPB to see if somebody can advise what kind of white bird is inhabiting my back garden.

To me, no expert, it looks like a blackbird, runs about the garden like a blackbird, has a yellow beak like a blackbird and other than the fact it is 99% white, had it been black or brown I would have sworn it was a blackbird.

Apologies for the photo quality - maximum zoom on an android phone - but it rarely stops for any length of time, never mind stopping for a bath!

Thanks in advance.