Rev Samba, pastor of the Church of Cherubs and Seraphs, was arrested on 26 October 2003 and is being held under harsh conditions in Evinayong Prison in Equatorial Guinea without charge or trial.
Food provisions in prisons across Equatorial Guinea are notoriously inadequate, while Amnesty International believes Rev Samba was arrested solely on grounds of his known peaceful political opinions and ethnic origin. The human rights group regards him as a prisoner of conscience.
In an article in this week's New Statesman, Dr Williams attacked the "ongoing scandal of imprisonment without trial as a sanction against peaceful dissidents or ethnic minorities".
"To let this go unchallenged in any area is to sell the pass for universal justice. And that is not an option for any religious person, or indeed anyone who thinks human dignities and liberties are more than a local arrangement for the convenience of the prosperous," he said.
Dr Williams went on to warn of the danger religious leaders face as they risk being caught in conflicts between "minority ethnic groups and arbitrary national administrations, from the old South Africa to East Timor".
"They deserve support from believers and unbelievers alike," he said.
"The energy for political liberation and the health of civil society depends massively on the churches in a great number of divided and deprived nations."
