The parish church of St Andrew at Irnham in Lincolnshire possesses a richly carved stone monument dating to around 1340 which bears the arms of Sir Geoffrey and Agnes Luttrell, associated with the celebrated Luttrell Psalter. The form, imagery and function of this monument are problematical and are discussed first in order to create a context for an unusual aspect of its architecture, namely that its inner vault is a miniature copy, unique in this part of England, of the main vault of the choir of Wells Cathedral, a so-called ‘net’ vault. Amongst the reasons for such an unusual citation may be the existence in Somerset, in the diocese of Wells, of one branch of the Luttrell family at the time this monument was raised.