Birdsong at Leytonstone Station

Recorded this on my Blackberry whilst waiting for the train this morning on the frosty platform at Leytonstone Overground Station. The singing bird was sat in a bare tree looking over the rooftops of E11.

Wish I could learn to identify birdsong and/or find my glasses and get them fixed. This was a small bird but at a distance of 20 yards just a blur so I couldn't see if it was the Robin I guessed it to be.