Baptism represents death and rebirth for Christians
Mr Hunt was then sent to Sunday school in west London and later to confirmation classes, but he decided early on that he had no place in what he felt was a hypocritical organisation.
He recalls that his mother had to get lunch ready early for him to attend the classes.
"One Sunday I came back home and said 'Mum, you needn't get lunch early next Sunday because I'm not going to the class any more'. And she decided not to argue."
Now Mr Hunt has become the pioneer in a rejuvenated campaign for a way of cancelling baptisms given to children too young to decide for themselves whether they wanted this formal initiation into Christianity.
However, baptism is proving a difficult thing to undo.
The local Anglican diocese, Southwark, refused to amend the baptismal roll as Mr Hunt had wanted, on the grounds that it was a historical record.
"You can't remove from the record something that actually happened," said the Bishop of Croydon, the Right Reverend Nick Baines.
"Whether we agree whether it should have happened or not is a different matter.
"But it's a bit like trying to expunge Trotsky from the photos. Mr Hunt was baptised and that's a matter of public record."
Instead the diocese suggested that the best way for Mr Hunt to renounce his baptism was to advertise it in the London Gazette, a journal of record with an ancestry going back to the 17th Century.
Bishop Baines is willing to see such notices inserted into the baptismal roll to indicate decisions such as Mr Hunt's, but the Church of England's national headquarters made clear that such a concession was not official policy.
A letter from the the Archbishops' Council said that the Church of England did not regard baptism as a sign of membership, so any amendment to the record would be unnecessary.
The Roman Catholic Church does view a person's baptism as incorporating them into the Church - and membership is later important to the Church if, for example, the same person wants to get married in a Catholic church.
It is willing to place an amendment in the record.
The National Secular Society would like the Church of England to devise a formal procedure for cancelling baptisms, with a change in the baptismal roll as part of it.
In the face of resistance from the Church, the society has come up with a document of its own.
The "Certificate of Debaptism" has a deliberately home-made look, with its mock-official decoration and quasi-official language.
Sitting on a bench in the grounds of St Jude's Church, John Hunt intoned the opening lines.
"I, John Geoffrey Hunt, having been subjected to the rite of Christian baptism in infancy... hereby publicly revoke any implications of that rite. I reject all its creeds and other such superstitions in particular the perfidious belief that any baby needs to be cleansed of original sin."
The society's president, Terry Sanderson, says the certificate is not designed to be taken too seriously, and he suggests displaying it in the loo.
However, he says, it has now been downloaded more that 60,000 times, and has taken on a life of its own.
"The debaptism certificate started out as a kind of satirical comment on the idea that you could be enrolled in a church before you could talk, but it seems to have taken off from there.
"People are beginning to take it seriously.