St Etheldreda's consists of a chapel, or upper church, and a crypt or undercroft, and is active and used for Masses, baptisms, weddings, and funerals.

In 1576 a lease on a portion of the house and lands surrounding the chapel was granted by Richard Cox, Bishop of Ely, to Sir Christopher Hatton, a favourite of Elizabeth I.

The rent was £10, ten loads of hay and one red rose per year, a small enough sum to give rise to suspicion that Elizabeth had put pressure on the bishop.

The day after we had made the purchase, the clergyman of the Welsh congregation called on me to offer a considerable advance on the sum we had paid.

In 1820 the chapel was taken over by the National Society for the Education of the Poor who hoped to convert the Irish Catholic immigrants then settling in the area.

In 1836, Ely Chapel was reopened by the Reverend Alexander D'Arblay (son of Fanny Burney) as a place of Anglican worship but he died the following year.

[3] The chapel was put up for auction in 1874 and purchased for £5,400 by the Catholic convert Father William Lockhart of the Rosminian order.

Under Lockhart's direction, the crypt and upper church were restored by George Gilbert Scott to their original 13th-century designs.

The church received a relic from the Duke of Norfolk: a piece of Saint Etheldreda's hand, which is kept in a jewel cask to the right of the high altar.

In May 1941, during the Blitz, the church was hit by a bomb that tore a hole in the roof and destroyed the Victorian stained glass windows.

It features the Trinity, the evangelists Matthew, Mark, Luke, and John, as well as the Virgin Mary and Saints Joseph, Bridget of Kildare and Etheldreda.

In the 1960s, two groups of four statues of English Catholic martyrs from the time of Henry VIII and Elizabeth I were installed along the north and south walls.