The Church of the Holy Trinity, built between 1648 and 1652, is one of the few churches in England constructed during the Interregnum — the period between the execution of Charles I and the Restoration of the monarchy. The absence of royal patronage shows in the architecture: the building is surprisingly spare and almost secular-looking by English church standards, its interior flooded with light from wide round-headed windows and free of the Gothic elaboration typical of the period.
The church has been much modified over the centuries, but the interior still retains its Commonwealth character. It stands in a quiet walled churchyard near the north wall, a short walk from the barracks. Admission is free and the building is usually open during daylight hours.