Deep Vein Thrombosis was added to the white man&rsquos burdens in 1924 when Britain&rsquos four private airlines were merged into the government subsidised Imperial Airways Limited. It wasn&rsquot until 1929 that the first scheduled flight from Croydon aerodrome reached Karachi (by way of Cairo and Basra). The De Havilland DH 66 Hercules carried eight passengers in an enclosed cabin. The poor pilots sat in an open cockpit and navigated across the Arabian desert by looking out for a furrow ploughed several hundered miles across the sands by ground staff. By 1931 Imperial passengers were flying to India in the four-engined, 24-seater Hannibal class Handley Page HP 42. It was the jumbo of its day, and had an unblemished safety record (although In Agatha Christie&rsquos 1935 thriller Death In the Clouds, a passenger is murdered aboard what is recognisably an HP 42). Imperial Airways itself ceased to be in 1939, well before the end of empire and was absorbed into the newly formed British Overseas Airways Corporation.