Listen: microphone captures exiting UK PM Cameron singing merrily to himself after handover announcement

British Prime Minister David Cameron appeared to be singing a little tune to himself as he walked away from cameras after announcing he would hand over power to his successor Theresa May on Wednesday.

Cameron stepped away still wearing his lapel microphone and could be heard singing to himself “doot -de-doo” as he reached the door of 10 Downing Street, his official residence, in video footage broadcast by ITV.

As the door opened, he could be heard saying “Right!” before it closed behind him and a scratching sound was audible, indicating the microphone was removed.

Moments earlier the departing Conservative Party leader had announced: “We’ll have a new prime minister in that building behind me by Wednesday evening”.

Views differed among political journalists on Twitter over what Cameron might have been singing after his momentous announcement on a day of high-drama in Westminster.

Bloomberg’s Rob Hutton said it sounded like the beginning of the theme song for the hit US political drama series West Wing, while ITV’s Robert Peston said it was just a “Winnie-the-Pooh style hum”.