Pour the bourbon, gin, lime juice and bitters into a shaker with ice and shake until well chilled (about 30 seconds).

Strain into a Collins glass over fresh ice.

Top up with the ginger beer.

Garnish with a sprig of mint.

Many classic cocktails have their origins in the bars of large hotels. The Singapore Sling comes from the famous Raffles Hotel in Singapore, while the Vieux Carré was first mixed at the Hotel Monteleone in New Orleans. The list goes on and includes the Suffering Bastard, which was originally developed by the bar staff at Shepheard's Hotel in Cairo as a hangover cure before the hotel burned to the ground in 1952.