It sounds like an American speaker speaking VERY slowly to me. The speaker is trying to speak clearly, so he's slowing down his speech and stressing every vowel. This doesn't sound like natural speech (I actually suspected it was a robotic voice at first), but it's hard to misunderstand.
I can see why you'd think it's RP - the speaker is speaking very slowly and over-enunciating every syllable, which is similar to a stereotypical, over-the-top posh British accent - compare the weird intonation and the over-enunciation in your recording to this old speech by the Queen: https://www.youtube.com/watch?v=mBRP-o6Q85s
Because they're both making an effort to slow down and speak clearly, their pacing and intonation are very similar, even if the accents themselves are completely different.