An bus drives past St Mary's Hospital where Catherine, Duchess of Cambridge is due to give birth in London June 20, 2013. Britain's Duchess of Cambridge, Kate Middleton, will give birth to the future heir to the British throne in the same hospital where the late Princess Diana gave birth to Princes William and Harry, royal sources said on Wednesday. The sources said the royal couple have still not been told the sex of the baby which is due next month as they want it to be a surprise.[Photo/Agencies]