Dr John Sentamu, who will be enthroned in York next month, said that although he was angered by the abuse, he prayed for those who had written the letters. He said: "I don't know where they are from. They don't tell you. They simply tell you, I am Mr White X and nigger go back and this is what you are like, this is what you are worth."
Dr Sentamu, 56, said it did not mean Britain was a racist country, and he believed the letter-writers represented a "tiny minority". The archbishop said: "It has been terrible. Some of it has been awful."
Asked if he felt angry, he said: "Yes, particularly when they had human excrement in them. I don't want to have those sorts of things, and I say, 'Why do people do this?'" But he told BBC Radio 4's Today : "In the end, when I get those letters, I actually pray for the person who's written them."
The new Archbishop of York, the second highest position in the Church of England, was educated in Uganda, where he practised as a barrister and was an outspoken critic of Idi Amin's regime, before coming to the UK in 1974.
He was ordained in 1979 and, after serving in a succession of London parishes, he was appointed Bishop of Stepney in 1996, and Bishop of Birmingham in 2002. All his life he has campaigned against racism and other forms of discrimination.
Dr Sentamu worked on inquiries into the 1993 racist killing of Stephen Lawrence and the stabbing in 2000 of the Nigerian schoolboy Damilola Taylor, and has said the Church of England contains institutional racism, just as a room full of smokers contains smoke.
During his six years as Bishop of Stepney, east London, he was stopped and searched eight times by the police. What upset him most was the sudden change in the officers' behaviour when they realised his identity.
He said at the time: "When they discovered who I was, the way I was treated was very different. They should treat everybody with respect, with dignity."
He has also been the victim of verbal and physical abuse. He recalled how four young white men spat at him and said: "Nigger, go back." He replied: "You have wasted your saliva."
In his interview yesterday he said: "This country, of all the places I have been to, is the most tolerant and welcoming of all places. Therefore, this tiny minority is not going to stop me from telling people that if we become a society of friends and a society that will discover the wonderful love of God and Christ, we have a chance of leading the nation in prayer."
When Mr Sentamu was born, the sixth of 13 children, near Kampala in Uganda in 1949, he was so small the local bishop was called in to baptise him immediately. He survived his birth, a sickly childhood and a famine to become, 25 years later, a judge in the Uganda High Court.
A spokeswoman for the Archbishop said yesterday that Dr Sentamu had been "deluged" with e-mails offering support and urging him to ignore the racist abuse. She said: "It has been rather heartening."
Dr Sentamu said on his appointment that he hoped that he would not be known as the "black Archbishop" but as "a leader who would show the world the way to God's love, grace and mercy".
He also acknowledged the Church's declining membership, its "ups and downs", and said it was too easy for a Christian tradition to become complacent.Reuse content