The Archbishops of Canterbury and York are asking people to take time this weekend to reflect on the horrors of the transatlantic slave trade and use the 200th anniversary of its abolition as a springboard for taking action to tackle the impact of the trade's legacies today, including human trafficking and oppression across the globe.

The Archbishops will lead hundreds of people, including foreign dignitaries and leaders of other churches, through London on Saturday for a Walk of Witness to mark the landmark anniversary. The event follows the apology given by the Church of England for its role in the slave trade, which the General Synod debated in February 2006.

They hope that the commemoration of the Bicentenary of the Act for the Abolition of the Slave Trade will become an agent for change in society and begin a process of healing.

Dr Rowan Williams, Archbishop of Canterbury, writes in the foreword to the walk's programme: "Some have said they see no need for the apology made last year by the General Synod for the role the Church played in the slave trade. But when we acknowledge historic injustices inflicted in the name of the Church, this is a vital part of our life as members of the body of Christ, a body that exists through time as well as across geographical and ethnic boundaries.

"This important anniversary, when we recall both the shameful history of the slave trade and its modern legacies, presents us with an opportunity to open up that past to the healing power of Christ."

In his introductory text, Dr John Sentamu, Archbishop of York, writes: "For me, faith is the spiritual engine of change. Thank God that old dualism between the personal and social Gospel is breaking down. We need to rediscover a new faith-based movement for social and economic justice, which has hope, rather than anger, at its core.

"I believe that movement is the Church and it is my hope that as we commemorate the achievements of the abolitionists over the coming months we might also re-dedicate ourselves to being that change which we want to see in the world."

The Walk of Witness will start at Whitehall Place, London, at 12.15pm and includes the culmination of the March of the Abolitionists - a group of walkers who have worn yokes and chains during a 250-mile journey beginning in Hull. When the walkers reach Victoria Tower Gardens, the Archbishop of the West Indies will release them from their chains.

After crossing the Thames, the Archbishops will pause by the river on the south Embankment and lead prayers while holding a wreath marked with '2704', the number of ships which departed from London's docks destined to carry slaves during the Transatlantic slave trade. Two young people will then take the wreath down a jetty into a boat, which will then move away from the riverbank and pause for a commemorative silence before continuing down river towards the docks.

The other start point for walkers marking the anniversary will be William Wilberforce's church, Holy Trinity Clapham, where a short service will take place at 1pm before walkers set off for Kennington Park led by bishops from the Diocese of Southwark.

The two walks will culminate in an open-air Act of Worship at Kennington Park.

The Archbishops of Canterbury and York will be joined by the Archbishop of the West Indies, the Most Rev Drexel Gomez, and the Archbishop of West Africa, the Most Rev Dr Justice Akrofi, alongside representatives of foreign governments including the Republic of Ghana, the Republic of Gambia, the United Republic of Tanzania, the Democratic Republic of Congo, the Republic of Cuba and the Netherlands. The Lord Mayor of Westminster and the leader of Lambeth Council will also be present.

A dedicated website, www.makingourmark.org.uk, contains full details of the routes, answers to frequently asked questions and the opportunity for people to sign up to join the walk.