Lord Mayor of Oxford Mary Clarkson helped to maintain an Oxford custom — Beating the Bounds.

Mrs Clarkson joined parishioners and the Rev Bob Wilkes for the Ascension Day tradition, in which members of St Michael at the Northgate Church walk around the parish, and use canes to beat stones marking the parish boundaries.

There are about 20 stones — including one in the middle of Marks & Spencer in Queen Street.

The two-hour walk finished at Lincoln College in High Street for the traditional lunch linked with the ceremony. The medieval custom is thought to have started at a time when there were fewer maps.

Beating the Bounds could date back as far as 1428, the year the ceremony was first mentioned in the churchwardens’ accounts for that year at St Michael’s.