Singh directed his BAFTA award-winning documentary about the world's most notorious mathematical problem entitled "Fermat's Last Theorem" in 1996. The film was memorable for its opening shot of a middle-aged mathematician, Andrew Wiles, holding back tears as he recalled the moment when he finally realised how to resolve the fundamental error in his proof of Fermat's Last Theorem. The documentary was originally transmitted in October 1997 as an edition of the BBC "Horizon" series. It was also aired in America as part of the NOVA series. "The Proof", as it was re-titled, was nominated for an Emmy Award.