(AFP) – Prince William on Thursday paid tribute to a generation lost at the Battle of the Somme, 100 years after the deadliest battle in British history. “We lost the flower of a generation and in the years to come it sometimes seemed that with them a sense of vital optimism had disappeared for ever from British life,” William said at a ceremony in northern France. “It was in many ways the saddest day in the long story of our nation,” he added, speaking on the eve of the 100th anniversary of the start of the World War I battle in which some 20,000 British soldiers died on the first day alone. William, his wife Kate and brother Prince Harry attended the start of an all-night vigil at the Thiepval memorial to honour the 1.2 million troops of different nationalities who were killed, injured or listed as missing. Britain’s Prince William, Duke of Cambridge (C) and his wife Catherine attend the commemoration of the 100th anniversary of the Battle of the Somme, on June 30, 2016 at the Thiepval Memorial Soldiers from the UK, France, Australia, Canada, Germany, India, Ireland, New Zealand and Pakistan will take turns maintaining the