China brushed aside international appeals Tuesday and executed a British drug smuggler who relatives say was mentally unstable and unwittingly lured into crime. Britain's prime minister quickly criticized the execution – China's first of a European citizen in nearly 60 years. “I condemn the execution of Akmal Shaikh in the strongest terms, and am appalled and disappointed that our persistent requests for clemency have not been granted. I am particularly concerned that no mental health assessment was undertaken,” Prime Minister Gordon Brown said in a statement issued by the Foreign Office. The press office of the Xinjiang region where Shaikh had been held confirmed the execution in a faxed statement. Shaikh, 53, first learned he was about to be executed Monday from his visiting cousins, who made a last-minute plea for his life. They say he is mentally unstable and was lured to China from a life on the street in Poland by men playing on his dreams to record a pop song for world peace. Brown had spoken personally to China's prime minister about his case. Foreign Secretary David Miliband also condemned the execution and said there were unanswered questions about the trial. “I also deeply regret the fact that our specific concerns about the individual in this case were not taken into consideration ... These included mental health issues, and inadequate professional interpretation during the trial,” Miliband said in a statement. China defended the case and criticized Brown's comments, saying drug smuggling was a serious crime. “We express our strong dissatisfaction and opposition to the British accusation,” Chinese Foreign Ministry spokeswoman Jiang Yu told a regular news conference. Jiang said she hoped the case did not harm bilateral relations, and called on London not to create any “obstacles” to better ties.