Sanctus bell, sanctus bell window. A bell rung at the consecration during Mass. In medieval practice, it was probably one of the bells in the tower, rung by an observer on the ringing platform - hence, the sanctus bell window in the west wall of many naves. Sometimes, the replacement of a roof in the 19th century has meant this being left above the roofline, exposed to the open air.

It called the attention of people at work in the fields or town to what was happening, enabling them to stop and pray for a moment. Some sanctus bells were located in the chancel, with the stirrups surviving on top of beams at Somersham and Hawstead, and there is a reconstructed sanctus bell turret above the nave at Southwold. Simpler sanctus bell turrets survive on nave gables at Worlington, Marlesford and Wickham Market, among other places. There is a very curious one at Felixstowe St Peter and St Paul, which doesn't seem to have been from the church originally.