Consisting of a single rectangular vaulted room, St Leonard's is just as it was built in the first years of the 13th century, except for the roof. Look up though and you will see fine mouldings and dogtooth ornament. At the intersections of the roof ribs are splendid bosses carved with foliage, with the eastern one having a representation of the Lamb of God in its centre.
The chancel screen retains two lengths of 13th century oak arcading. These are extremely rare examples of screen work and are probably the earliest in existence. North of the altar, is the upper two thirds of a marble effigy of a knight, bearing a sword and shield. The head rests on a pillow from which issue sprays of foliage. This is one of the earliest military effigies in England.