St Mary Magdalene is a rare example of a substantially complete 12thc. chapel, surviving on a most unlikely site on the busy Newmarket Road, alongside the disused Barnwell Junction railway station, and opposite Cambridge United football ground. It is a small, two-cell church with a square-ended ashlar chancel, originally vaulted, and a pebble nave with brick repairs. The outer angles of both nave and chancel have stone quoin shafts. The roof was renewed in the 15thc. The chapel fell into disrepair and when Cotman illustrated it in 1819 it was in use as a stable. Sir George Gilbert Scott restored it in 1867, and he was responsible for the main W window. 12thc. sculpture includes the lavish N and S doorways and nave and chancel windows, external and internal decorative friezes, the quoin shafts mentioned above, and the chancel arch.

The earliest documentary evidence for the chapel is in the Pipe Roll for 1169. According to Pearce, it was built at the beginning of the 12th century as part of the nearby Leper hospital of St Mary Magdalene. The present author prefers a date in the 1130s (see VIII). In 1211 King John granted the lepers the right to hold a three-day fair on the Vigil of Holy Cross. Stourbridge Fair became one of the great fairs of Europe, and survived until 1933. Rent from the stalls and booths added to the lepers income, which was otherwise derived from begging on the roadside, and from crops which they grew. In 1279 the hospital ceased to receive lepers and the Chapel was transformed into a free chapel — there was no associated parish at this time. In 1751 the Chapel ceased to be a place of worship, instead being used to store stalls between fairs. In 1783 it was advertised for sale as a store shed. After changing hands several times, in 1816 it was bought and restored by Thomas Kerrich, who then gave it to the University, who in turn gave it the Cambridge Preservation Society in 1951.

It seems probable that a workshop from Ely Cathedral was responsible for the sculpture here. Specific features with parallels at Ely are the sawtooth and billet string courses and the forms of chevron on doors, windows and chancel arch. The sawtooth and billet are found in the earliest work at the cathedral, and continue throughout the building of the nave (c.1100–20), and the lower storeys of the SW transept. It is in the external gallery of the SW transept that the closest parallels for the forms of chevron found in the Leper chapel occur. This workshop was at Ely in the late 1120s, and may have come to Cambridge in the 1130s. The forms of scallop capital with decorated shields found on the chancel arch suggest the later date.