A retired businessman said it was a "disgrace" that a radical cleric who poses a threat to the UK's national security has more rights than he has as he was extradited to the United States.
Christopher Tappin, who lost his two-year battle against extradition last week, said Abu Qatada had been allowed to stay in the UK, but he is being forced to leave.
The extradition of the 65-year-old Briton under the controversial UK-US treaty will increase pressure on David Cameron's Government to review the arrangements.
Mr Tappin, who faces up to 35 years in jail if convicted of arms dealing charges, said: "I look to Mr Cameron to look after my rights and he has failed to do so. I have no rights. Abu Qatada is walking the streets of London today and we cannot extradite him. He has more rights than I have.
"If I was a terrorist, I would not be going to America. I think it's a shame, a disgrace. The Conservative government, while in opposition, promised to reform the law and they failed to do so and they've let me down, they've let you down, they've let the whole country down."
The Government has been blocked in its attempts to deport Qatada to Jordan, where he faces terror charges, after the European Court of Human Rights ruled that further assurances that evidence gained through torture would not be used against him were needed before he could be sent back.
But the Prime Minister's official spokesman said: "They are completely different cases."
Mr Tappin, whose tearful wife Elaine was at his side, said he is full of trepidation and is "not sure what's going to happen", but added that he is keen to prove his innocence.
Mr Tappin, who has been caring for his wife who has chronic Churg-Strauss Syndrome, said he is "not very confident at all" about his case, mainly because his UK-based witnesses will not travel to the US and the American authorities do not allow video interrogation.
His lawyer Karen Todner said Mr Tappin, the former president of the Kent Golf Union, would arrive in El Paso, Texas, around 4pm local time (10pm GMT), where he will be remanded in a local jail until Monday, pending a bail hearing at the US district court in the western district of Texas.