BEIJING  Diplomatic officials and rights groups in Britain are waging a campaign to save the life of a British man who has been sentenced to death for drug smuggling by a Chinese court despite apparent signs of mental illness.

If the sentence is carried out, consular officials say, he would be the first British citizen to be executed in China in recent memory.

Although China puts more people to death than all other nations combined, it rarely executes foreigners, who are generally treated more leniently by the criminal justice system.

Family members and associates of the man, Akmal Shaikh, 53, say he was suffering from psychosis two years ago when he stepped off a plane in northwest China carrying a suitcase packed with nearly nine pounds of heroin. According to those advocating on his behalf, Mr. Shaikh told the police he had come to China to become a pop star and that he had been handed the suitcase just before boarding the plane in Kyrgyzstan by a man who said he would make him famous. The man, who promised he would follow on the next flight, never arrived.