Jay Buchanan's voice.

"I wasn’t really expecting much when I clicked on this video, but… WOW! I was totally knocked out by this sublime cover of Crystal Castles’ “Untrust Us” by UK-based Capital Children’s Choir. " - dangerousminds.net...

This is quite a cover, since they're just two guys attempting to perform a song by the best prog. rock trio in the world. Nice catch!