Mr Butt, whose brother Shahid was yesterday jailed for five years in Yemen, told an emotionally charged London press conference that the "joke trial" had been a nightmare. Breaking into tears as he ploughed through a prepared statement, Mr Butt could not hide his frustration at perceived Foreign Office inactivity, which he said bordered on the institutional racism exhibited during the Stephen Lawrence murder inquiry.
"Every time we have turned to official sources we have had the door slammed in our faces," he said. "We must not let this become another Lawrence tragedy. I am completely devastated and have the impossible task of going home to explain to my family and my brother's four kids, including his son Mulahim who cries every night for his father, that their father won't be coming back home."
His anger was shared by Atif Ahmed, the brother of Samad Ahmed, also jailed for five years. Mr Ahmed said British diplomats were guilty of "double standards" in dealing with Anglo-Asians abroad.
Rashad Yaqoob, the campaign's legal adviser, said: "This is an opportunity for the British Government to demonstrate the commitment that it does not at all look at race or colour when fulfilling its legal obligation to protect all its citizens abroad." The Government's perceived handling of the affair has angered the British Muslim community.
Last night, Peter Hain, a Foreign Office minister, said Tony Blair and Robin Cook, the Foreign Secretary, had made their concerns clear to the Yemeni Prime Minister.
He said: "We continue to take seriously the allegations that some of the men were tortured whilst in custody. The Prime Minister is writing to President Saleh."
Downing Street said the letter would be sent within 24 hours but the details would not be made public.
It was too little, too late, according to one campaign lawyer, Natalia Garcia. The Foreign Office, she said, had bitterly opposed - and ultimately defeated - attempts by Mr Butt's family for a judicial review of the official handling of the men's case in both the High Court and the Court of Appeal.
Abu Hamza al-Masry, the north London cleric who the Yemenis maintain organised the alleged terror campaign, said he was not surprised at the verdicts. His 17-year-old son Mustafa Kamel was among those jailed.
"Of course as a father I am disappointed and also for the families I am disappointed. They have been caught in a vicious crossfire ...I can see from the trial that it has been just a retaliation against me."
Iqbal Sacranie, secretary general of the Muslim Council of Great Britain, appealed to the President of Yemen, Ali Abdullah Saleh, to show mercy on the convicted men and let them come back to Britain.
He also said the episode showed that the Muslim community needed to pay more attention to its "alienated youth".