The first wave of Olympic athletes and visitors began pouring into London today. British officials played down fears that a packed London would buckle under the pressure of its biggest peacetime security and transport operation. Lately, preparations for the Games have been overshowed by shortage of security guards, fears over airport queues and questions about the capital's creaking transport system. Less than two weeks before the opening ceremony on July 27, Prime Minister David Cameron told a news conference in London that his government will do whatever it takes to deliver a safe and secure Games. Some 12,500 police will be on Olympics duty each day, backed up by soldiers, fighter jets and missile batteries on the top of apartment blocks near the Olympics site in east London.