Only 20 years later, work began on the second complex that was to be nearly four times larger (170m square) and took 30 years to complete. A complicated building programme was devised to ensure that business could continue during the building works (LCT84). This required the clearance of that part of the town centre.
Houses were cleared away and were gradually demolished as people moved out. Some buildings were converted into site stores and huts for the construction workers with mortar mixing pits and foot-print evidence for the pack animals needed to bring the building stone to the site.
The first forum and basilica had internal colonnades added to the south wing, while the north, east and west ranges of the later complex were being constructed. In the first phase, the basilica was built, the largest to be built north of the Alps.
Sited to the north of the forum, its three storeys would have been visible from all parts of the city. It was a large hall with a nave and northern aisle, adjoining which was a double row of offices.
On the northern side of the nave was a range of offices with a row of shops beyond. At the eastern end of the long nave that ran the length of the building was an apse and portico where the tribune, a raised platform for the judges, would have been sited.
In the same phase the east and west wings of the forum were built incorporating three ranges of rooms – two sets of shops or offices with an external portico. An inner portico facing the courtyard was a later addition and the two wings may have been connected with a central colonnade across the courtyard.
The first building was then demolished and the final southern wing completed the later complex. The south wing was a single range of rooms with internal and external porticos and a major monumental entrance. The forum, consisting of three wings, enclosed a rectangular courtyard measuring 100m east-west and 85m north-south.
The enlarged complex meant a new road layout around the complex which attracted new buildings and commercial premises to the area.
Although a major public building, seemingly built with considerable forward planning, it suffered major structural faults and throughout the 2nd and 3rd centuries there were various repairs and modifications and damage caused by fires and subsidence was sometimes patched up, but for long periods the main rooms lay partially neglected.
At the beginning of the 4th century (in about AD300), the walls, except perhaps for the southern range of the forum, were systematically razed to the ground and the area was left as an empty space. This demolition may have happened as punishment for London supporting Carausius in the late 3rd century, who had declared himself emperor of Britain.
The southern range of the forum may have been still in use as offices and perhaps a market used the vacant space behind. The basilica had been dismantled but the apse at the eastern end may have been left and turned into a temple or even a church.
For details of what can be seen of the basilica today, see Basilica and forum in Londinium Today. Information about Carausius can be found in The 'British Empire' in Military life.