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.

100% American, Igor. He's not trying to imitate any accent. He's reading deliberately and clearly and neutral. I detected a very, very slight east coast accent. But it's not enough to even be remarkable. This is most likely for learners of English. Am I correct?

It doesn't sound like RP. It's just a neutral American accent.

American. I can't pinpoint a strong regional accent. BTW, I don't hear RP at all. It doesn't sound like RP. It doesn't sound like the speaker is trying for RP and missing. It sounds thoroughly American to me.

Several RP vowels are different from US English vowels. It’s easy to hear the difference when you have learned to speak RP - which I have. Notice: glass: RP ​ /ɡlɑːs/ US ​ /ɡlæs/ bottle: RP ​ /ˈbɒt.əl/ US ​ /ˈbɑː.t̬əl/ UPDATE: It's actually easier to hear the difference with rob:​ RP /rɒb/ US ​ /rɑːb/ row: RP ​ /rəʊ/ US ​ /roʊ/ fall: RP ​ /fɔːl/ US ​ /fɑːl US English is generally rhotic, RP is not rhotic. Rhotic means that an /r/ is pronounced in all situations where there is an "r" in spelling. Try looking up the words above and listen to the difference between RP (UK) and US pronunciation here: http://dictionary.cambridge.org/