Several grooves and scratches can still be seen in the stonework of the tower. Local tradition holds that they were made by soldiers of the Parliamentary Army who passed through or camped in Grandborough before the Battle of Naseby in June 1645. According to the tradition, soldiers sharpened their swords against the church stonework, leaving marks that remain visible today. The marks provide a fascinating link between St Peter's and one of the most significant events of the English Civil War.