Church of England canon law states:
The churchwardens when admitted are officers of the bishop. They shall discharge such duties as are by law and custom assigned to them; they shall be foremost in representing the laity and in co-operating with the incumbent; they shall use their best endeavours by example and precept to encourage the parishioners in the practice of true religion and to promote unity and peace among them. They shall also maintain order and decency in the church and churchyard, especially during the time of divine service.
It seems clear that the incumbent minister ('vicar') could never legally be churchwarden. But could another ordained minister of the Church of England who worships in the parish become churchwarden?