London: British Prime Minister David Cameron described Nigeria and Afghanistan as "fantastically corrupt" in a conversation with Queen Elizabeth II. The conversation took place at Buckingham Palace on Tuesday during an event to mark the Queen's 90th birthday, attended by political leaders and other public figures. The prime minister was speaking to the Queen about this week's anti-corruption summit in London, BBC reported. "We've got some leaders of some fantastically corrupt countries coming to Britain... Nigeria and Afghanistan, possibly the two most corrupt countries in the world," he was overheard saying. After Cameron's comments, Archbishop of Canterbury Justin Welby intervened to say: "But this particular president is not corrupt... he's trying very hard," before Speaker John Bercow said: "They are coming at their own expense, one assumes?" In response to Cameron's comments, Nigerian President Muhammadu Buhari said his government was deeply "shocked and embarrassed" by the premier's comments. Hhe suggested that Cameron must be referring to Nigeria's past notoriety for corruption before his coming to power last year. Meanwhile, the Afghan embassy in London said tackling corruption was one of President Ashraf Ghani's top priorities and "bold" action had been taken. "We have made important progress in fighting systematic capture in major national procurement contracts and are making progress on addressing institutional issues as well as issues related to impunity... Therefore calling Afghanistan in that way is unfair."