Campaigners have targeted a Birmingham firm which they say makes "shackles" used at the Guantanamo Bay camp.
Human rights campaigners have criticised Guantanamo Bay
Comedian Mark Thomas joined protesters in orange jumpsuits from pressure group Reprieve outside the headquarters of Hiatts in Birmingham.
Reprieve believes inmates are mistreated at the US camp and should be charged or released.
The handcuff makers, established in 1780, are refusing to comment on Reprieve's allegations.
The US says it has rigorously upheld human rights at Guantanamo Bay and that many of those detained have been involved in terrorism.
Reprieve is angry that Hiatts is supplying the "shackles", despite the allegations of human rights abuses at the camp in Cuba.
Group members also want the UK government to do more for British residents held by the US.
Nine British citizens have been released from Guantanamo Bay, but there are understood to be at least five British residents still held there. Activists say they are on hunger strike.
One of them, Oma Deghayes, 36, from Brighton, has reportedly not eaten for nearly five weeks in protest at his treatment.
His brother Abubaker, who was among the protesters, said: "I'm really worried. Something really needs to be done.
"We always thought we were entitled to justice, freedom and human rights. Our government tells off countries like China and Russia about their human rights record but not America. Is this acceptable?
"Please, please, please, our plea to the British government is to do something about this distress and cancer."
'Can't ignore message'
The protesters were accompanied by a folk band, and Birmingham doctor David Nicholl, who recently ran the London Marathon in an orange jumpsuit.
Dr Nicholl has written to Hiatts asking if the company will voluntarily ban exports of handcuffs and all other restraints to the US as long as torture and ill-treatment continues.
He said: "We felt we had to deliver a message that [they] couldn't ignore."
Lawyer Clive Stafford-Smith said: "My British clients, some of whom came from Birmingham, did not enjoy being reminded of home by the shackles on their wrists.
"If an ethical foreign policy means anything, it means not profiting from the torment of our own people. The most effective counter-terrorism weapon available is to respect human rights, not abuse them."