It seems that Birley and three chums have formed a rock band called 50:50. They haven't booked the new Wembley Stadium quite yet, but last week they did play at a pub in Herne Hill.
'From the outset, Birley showed Keith Moon-like exuberance in an effort to single-handedly outplay the rest of the band from his drum kit,' says our spy, Jim Long, international PR manager at whisky firm Chivas Brothers. 'This was eventually achieved when he took over the lead vocals for the Warren Zevon classic Werewolves of London.'
Long continues: 'Birley stepped up to the mark for the chorus with spine-tingleing howls of ahhhoooo!'
Yikes! Shades of Liam Gallagher. Sort of. But next time, how about a nice bit of James Blunt, chaps?