The International Baccalaureate Organization (IBO), a Geneva-based body whose diploma is much sought after by thousands of Greek students, yesterday revoked the operating license of a Greek private school offering the diploma over allegations that one of its teachers had leaked examination answers to some of his students in advance of tests in May. The IBO's decision will reportedly not affect students who sat examinations in May, and those in their first year of study will be allowed to complete their second year. But the Ziridis School will be banned from offering the diploma as of next year. A spokesperson for the school said an internal probe «suggests the existence of an organized racket around the IB program.» «We will not tolerate the unfair targeting of our school,» the spokesperson said, noting that legal action has been taken against the implicated teacher. Greek authorities are probing the teacher's alleged misdeeds.