The church stands on Franciscan Way, part of the Ipswich inner ring road, in an area of office buildings between the town centre and the docks. It became redundantc.1980 and came into the possession of Ipswich Borough Council, who rented it to the Ipswich Historic Churches Trust. In 2001 the Diocese bought it from the Council for £1, in order to convert it into a flexible meeting place in the centre of Ipswich for the church, community, business and charities. It includes a conference, meeting and performance space, a bookshop and a restaurant. The church consists of a nave with aisles of flint and rubble construction, of four bays without a clerestorey but with 15thc. dormers at the east end to light the rood area. The arcade, S doorway and aisle windows suggest a date ofc.1300. The aisles were extended for one bay alongside the chancel in the 15thc., and on the N side a knapped flint gabled chapel was added E of this, which is now the Revelations bookshop. On the S side of the chancel, a passage leads to the glass-walled restaurant of 2004-05. The S nave doorway is protected by a brick porch. The W tower is 15thc, of knapped flint with diagonal buttresses and an embattled parapet with elaborate flushwork and crocketed pinnacles. It was rebuilt in 1886. St Nicholas's has no Romanesque fabric but houses the most celebrated Romanesque sculpture in the county: a tympanum carved with a boar, a relief of St Michael and the Dragon and three reliefs of apostles.

Neither (i) nor (ii) came from St Nicholas' church originally. For (i), there was a church of St Michael recorded in the Domesday Survey as a possession of Wulfwine the Priest, and it later belonged to the Priory of the Holy Trinity, begunc.1177 by Normanius Gastrode, filii Egnostii. St Michael's appears in a charter of King John listing the possessions of the Priory at the beginning of the 13thc. The present All Saints' church is of 1885-87 by S. Wright of Lancashire. Speed's map of 1610 does not show a church with this dedication in Ipswich, although there was a chapel of All Saints in the parish of St Matthew.

This former parish church is now a community and conference centre.

The most thorough analysis is in the two articles by Galbraith, who suggested that the boar tympanum's obvious phallic reference made it a fertility symbol. The motif is more common in Scandinavia than England; it is found in the Gotland churches of Väte and Grötlingbo. It is unusual to find tympana with carving on both faces. Enclosing the design within this kind of heavy border, inside the edge of the block, is unusual too but it is found within the county on a relatively plain tympanum at St Peter's, Baylham. Zarnecki (English Romanesque Art) dates (i) and (ii)c.1120 and relates them to the Ringerike-influenced Guildhall grave slab, but this was made some 70-100 years earlier and the similarities are not striking. Pevsner compares the style of the St Michael relief to a lintel at Hoveringham (Notts).