The opinions of a person ...
You wish, McTag. It's amazing how folks like you, proven oh so wrong can keep coming back with the same bullshit. That is out and out delusion, McTag.
Given proof that you are out to lunch and you don't even raise your famous, "Well, my ma and pa taught me different.
You obviously can't be trusted to give an accurate, honest assessment of the situation even for BrE.
I'm actually glad that we've had this little go round because it highlights for ESLs/ENLs, me and others that you are not to be trusted when it comes to language issues.
Google exact phrase search
UK region pages
"may I have"
About 1,880,000 results
UK region pages
"can I have"
About 19,900,000 results
The Longman Grammar of Written and Spoken English [LGSWE] - pg 491
Frequency per million words of permission modals CAN COULD MAY MIGHT
CAN 850 COULD 200 MAY 70 MIGHT very low [page 491]
As you can plainly see, CAN for permission is far and away the most common modal used for permission. COULD is a distant second and MAY is but a blip relative to the other two.
Despite a well known prescription favoring may rather than can for expressing permission, may is especially rare in the sense of permission. Interestingly, many of the instances of may marking permission in the LSWE Corpus are produced by caregivers in conversations with children: [page 493]
What can be drawn from the last quote is that if there weren't these idiots, like you, around trying to drum unnatural rules into kids' heads the frequency of may
for permission would be low indeed.
Now this is not to say that it would be absent, gone, dead, for REALISTIC approaches to language recognize what actually occurs. Why haven't you language experts been pushing MIGHT because MIGHT is even more polite, more deferential than MAY.
You know, if this had been approached in an honest fashion, prescriptivists would have a better reputation. Instead of creating the absolute fiction that CAN is limited in meaning to 'ability' - god, that's so dumb, not to mention delusional!!! - why not be honest and describe that MAY is something that can be used to be more polite/more deferential/softer.