"Normalise" or "normalize" (British English)?

Is normalise perhaps obsolete in British English, and normalize preferred instead?

I have done some Googling, it seems British English dictionaries prefer normalize, but I haven't found any satisfactory answers from native speakers. I would like to hear about usage and "how it sounds" (the formality), maybe if there are any reasons to use both forms in different situations.

(The question arose when reading something about vector normalization.)

Solution 1:

In my experience (as a BrE speaker who works in IT, where I suppose the word does sometimes crop up), "normalise" definitely isn't obsolete. I use "normalise", and similarly I stick to "realise", "formalise" and so on. Many Brits use "ise" endings and many use "ize", not just for "normalis/ze" but for all the rest. Each person is likely to be consistent in their own usage. I can't imagine anyone using an "ise" ending for most such words but then switching to "ize" for "normalize" - that just seems inconsistent for no good reason.

Solution 2:

I am not a native speaker, but I am in IT spell it with a Z in code comments

Google NGram produces these graphs

British American