The Archbishop of Canterbury, Dr Rowan Williams, and the Archbishop of York, Dr John Sentamu have published an innovative online reflection on the nature of the slave trade in readiness for the Church of England's Walk of Witness to take place in London on Saturday March 24.

The joint reflection has been posted on 'youtube', and was filmed at the site of the slave market in Zanzibar, now the island's Anglican Cathedral, during the recent Anglican Primates Meeting.

The Church of England's two most-senior archbishops were shown two small preserved slave pits, where up to 175 men, women and children were held in appalling conditions, chained and in darkness, often without food and water.

Archbishop Sentamu spent some time at a memorial to the slaves which features some of the original chains used when the market was operating.

In the film, Archbishop Williams says that the experience brought home the reality of the trade: "You see there the fetters that were used for slaves, the fetters used to bring slaves in convoy, so that they could barely stand and walk, they were so closely shackled together; and to see some of the real, the actual shackles that were used until really very recently in this part of the world as part of the paraphernalia of the slave trade, it's a reminder that it really happened, it really happened not very long ago."