"Down Under" was huge. This jokey ode to legendary Australian wanderlust helped Men at Work win a Grammy and was a key part of the band's creative legacy. By 2007, it had been earning Men At Work a steady stream of royalties for nearly 30 years. That was when a quiz show pointed out the song's subtle connection with an Australian nursery rhyme...

Tim Harford examines one of the most controversial copyright battles in music history. Where does inspiration end and infringement begin?

For a full list of sources, see the show notes at timharford.com.