The Croutons are a vocal trio based in SW UK. They choose songs they love from a variety of genres, both classic and contemporary, and give it their own twist using just 3 voices and a vocal looper. They can be contacted via their Facebook page (which contains video) or their web page, which has studio recordings as well as live tracks. This one is from their third BBC Radio transmission for BBC Radio Five Live. 

Web page: http://www.singingwithattitude.com/The-Croutons.html
Facebook page: https://www.facebook.com/pages/The-Croutons/320173548020187