The day Sir Paul McCartney dropped by unannounced

In this video former Wings guitarist Henry McCullough returns to The University of Nottingham with the BBC's One Show, nearly 40 years after one of rock's most surprising debut gigs.
Students on campus refused to believe that former Beatle Sir Paul McCartney and his new band Wings had turned up at the Students' Union in an old van to play a gig in the early spring of 1972.