There are different kinds of Baptism, both performed by the minister of the church concerned. Infant baptism (often called christenings) and Believers baptism (total immersion together with profession of faith in Jesus) The latter is usually performed in Baptist or Evangelical church after a person becomes a Christian to show their new found faith. The new believer is put under the water in a pool for a second or two to represent Jesus dying and then raised to new life. Special baptistry pools are built under the floor at the front of many Baptist churches. The former is performed when babies are baptised (christened) at a font in the church, often with water placed on the head of the infant while prayers, promises or vows are made by the parents and/or the godparents. This is usually performed in C of E churches while in Baptist and Evangelical churches babies are not "christened" but "dedicated" - this is a simple dedication service where the Pastor or minister holds the baby and prays a prayer of thanksgiving and blessing for the safe birth and for the child's future. At each of these different ceremonies, to my knowledge, it is always the vicar, pastor or minister who performs the service, I have never heard of anyone else doing it. Hope this helps.