British upper-class pronunciation of words like “what” and “when”

Question

More from the BBC adaptation of Charles Dickens' Bleak House.

I've noticed in these sort of movies, when some very upper-class speakers talk, like the lawyer in the series, Mr. Tulkinghorn, they have a distinct way of pronouncing "wh" in what and when; the "wh-" sounds seems to be prefaced with an almost sharp whistling "h", so that it sounds like they are really saying hwat and hwhen.

I'd like to know three things: First, what is the specific name of this phoneme, as would be given by linguists? Secondly, what's the difference in articulation, in terms of tongues and throats, between this hwh- and wh-? And finally, the most difficult question of all: Is the hwhat these upper-class speakers produce a direct-line preservation of Anglo-Saxon pronunciation, through these many centuries? [I ask because I have seen the construction "hwæt hwæt" used playfully as an example of Anglo-Saxon speech, and figured that the "hw-" sound must have prominent in that language.]

Answer 1

Only a few dialects maintain the distinction between /hw/ and /w/, that is, distinguishing witch from which, wale from whale, and wine from whine. The WH sound, a voiceless labiovelar approximant, is written as /hw/ or sometimes /ʍ/ in the International Phonetic Alphabet. The W sound is a voiced labiovelar approximant. The difference between the two is that the WH sound is voiceless, meaning it is produced without vibration of the vocal cords (at least at the beginning), whereas the W sound is produced with voicing (vibration of the vocal cords) throughout.

Wikipedia has a good article summarizing the phonological history of the WH sound.

Answer 2

I believe that the hwat is actually "proper English" and most of us slur it. At least that's what my (American) english teacher in elementary school would have us believe.