The British Expeditionary Force to China departed London in the spring of 1857, becoming one of the first large groups to travel on the new railway linking Alexandria and Cairo across part of the Isthmus of Suez. Lord Elgin's command arrived in Hong Kong on July 2, where they received news of rioting among native Indian troops in the Sepoy Army of Bengal that been underway since early May of that year. After diverting a large contingent of British troops to India to help put down the rebellion, Lord Elgin's command rode at anchor off Hong Kong for two long months during the height of summer. In September, Lord Elgin received authorization from Lord Clarendon to take Canton by force and spent the next few months working with French Ambassador Baron Jean Baptiste Louis Gros and the French command on the details of their joint operation.