Family members of a British man due to be executed this week for drug trafficking are expected to arrive in China today in a last ditch attempt to plead for his life, a rights group said.

Akmal Shaikh, a 53-year-old father-of-three who supporters say suffers from bipolar disorder, faces execution on Tuesday for drug smuggling after losing his final appeal in China's Supreme Court.

Britain opposes the death penalty and Prime Minister Gordon Brown has repeatedly raised Shaikh's case with China's leaders and appealed for clemency.

Shaikh's cousins Soohail Shaikh and Nasir Shaikh were scheduled to arrive in Beijing Sunday and transfer to a flight to western China's Xinjiang region where the execution is expected to take place, the London-based legal aid group Reprieve said.

"Once there, they will deliver legal petitions seeking review of the case to the local court that originally imposed the death sentence, as well as the Supreme People’s Court," a statement from the group said.

They will also deliver a plea of mercy to Chinese President Hu Jintao and the National People's Congress, which receives petition's for pardon or clemency, it said.

'Duped by a criminal gang'

The two cousins also hope to meet with Shaikh in the Xinjiang regional capital of Urumqi ahead of his scheduled Tuesday execution, it added.

"We plead for his life," Soohail Shaikh stated in the petition for clemency, "asking that a full mental health evaluation be conducted to assess the impact of his mental illness, and that recognition be made that he is not as culpable as those who might, under Chinese law, be eligible for the death penalty."

Shaikh's brother Akbar has already written to Fu Ying, Beijing's ambassador to London, appealing for the Chinese authorities to show mercy.

Shaikh, from London, was arrested in September 2007 in Urumqi with four kilogrammes of heroin. Campaigners say he was duped into carrying the drugs for a criminal gang.

If the death penalty is carried out, Shaikh would become the first national from a European Union country to be executed in China in 50 years, Reprieve said.