The Parish of Traprain has adopted the Unitary Constitution. The Kirk Session is responsible not only for the spiritual but also the temporal affairs within the united parish. Some committees were established to oversee finance, fabric and fundraising and some members, who had belonged to the Congregational Board, were co-opted onto the Kirk Session to continue this work. The Kirk Session meets five times a year.
Members of the Kirk Session are elders chosen from the membership of the church who are considered to have the appropriate gifts and skills. Apart from attendance at Kirk Session meetings and taking part in the decision making process, elders are responsible for a district within the parish; visiting and taking an interest in the spiritual well being of the people in their care. Elders issue invitations to attend communion services and assist the minister in serving the bread and wine at the Sacrament.