The 13c Lady Chapel was once free-standing and separate from the main building. Now it is entered through an early English archway. The eastern bays were destroyed during the Reformation, but the remaining bay with Purbeck marble shafting hints at how magnificent it must have been. During the Elizabethan period, the school's headmaster's house lay transversely across this area and the square-headed mullioned windows above the eastern arch lit the second floor of the house. (see also the Chapel of St. Mary le Bow) The east bay is modern and was added when the chapels were restored in 1921. The architect was W D Caroë.
The glass reredos was designed and engraved by Lawrence Whistler in 1969. It is a masterpiece that portrays the symbolism of the Blessed Virgin Mary where her crown of roses and lilies surmounts a winged heart with the arms of her initial 'M' evolving into the wheat and grapes of the sacrament.