The BBC has unveiled the trailer for its 70-day coverage of the London 2012 Olympics torch relay, featuring specially commissioned music from the Mercury Music award-winning band Elbow.

The advert features a taster of Elbow's Olympics track "First Steps", composed by the band and performed with the BBC Philharmonic Orchestra and The Olympic Choir.

A full version of the track will be launched for the BBC's Games-time marketing campaign and will be used in the BBC's Olympic title sequences.