What are the new busking classics?

IN LIVERPOOL, on Saturday, in the heart of the Cavern Quarter (where it all began, folks!) I saw a brilliant, insanely good looking lad busking Kings of Leon's Sex on Fire, note perfectly.
I didn't have camera capable of high quality video footage, but it was a great scene. He was surrounded by a load of Geordie stag trip drunks all tunelessly and enthusiastically joining in.
Allied to the fact that Liverpool now has its own version of kora genius Toumani Diabate (above film) and the blind lad who does Shadows-style instrumentals of YNWA (among others), maybe one of our Capital of Culture dividends is an increase in quality in the busking community.
But it has got me thinking, what are the new busking classics?
An old Q magazine (probably in the Du Noyer editorship era, 1990ish) did a round-up of old busking classics, Cavatina, Streets of London et al.
But what are the songs that have become the new busking classics and what are the songs that could never become busking songs, within reason obviously.