It's critically-acclaimed Oxford indie rockers Foals, with instrumental track Like Swimming taken from their 2008 debut album Antidotes.
Foals have long been an integral part of the arsenal of great British indie bands that really got me interested in music: I'm talking of course about the likes of Foals, Arctic Monkeys, early Muse, Bloc Party and the Maccabees, to name but a few (of the good ones).
Like Swimming has a distinctly math-rock feel to it, formed of an amalgam of sparkling guitar melodies which percolate their way through a basic drum rhythm enhanced with the use of handclaps and subtlety-placed tambourines, the song gradually crescendoes to its climax before being swept away by a wash of static.
For fans of intricate indie-rock, built around guitars, and, when their not fashioning instrumental soundscapes, compelling open-plan vocals. See also: Bloc Party, The Maccabees, Vampire Weekend.