It will be among the star exhibits when a new £6.6m Roman baths museum is completed in Tower Street by the district council.

The so-called 'Jupiter stone', dating from the late second or early third century, is just too big to be exhibited in the present museum building, but a new high-profile role for it is now being planned.

The announcement is made in the latest issue of the district council's annual Past Matters publication.

The stone is believed to be part of the base of a statue or column for the god Jupiter, originally sited in the forum at the heart of the Roman city of Chichester.

Whichever it was, archaeologists say there was almost certainly a statue of the god Jupiter on top of it – larger than human-size – and towering over the public place.

A statue of this kind, featuring the principal god, was the ultimate expression of 'official' Roman religion. Similar ones have been found in other Roman cities in the empire, always right in the centre.

The Jupiter stone was found in 1935, during the construction of the Post Office in West Street, and an article in Past Matters said it was rescued at the last minute by local archaeologists, who prevented it from being broken up into hardcore.

"The stone depicts as nymphs a pair of female divinities that are apparently based on adaptations of representations of the Three Graces," the magazine added.

On other sides of the stone were an inscription to Jupiter, a depiction believed to be of the goddess Minerva and a male god or hero.

Other recent archaeological finds across the district are also highlighted in the magazine – more than 550 were made during last year.

They include a complete Roman flagon unearthed while British Telecom was replacing cabling in St Pancras, near the Observer's offices.

The magazine said although there was a large Roman cemetery in the area, very little had been expected to be found, considering the amount of ground disturbance over the years.

The flagon, typical of Roman pots dating mainly to the second and third centuries, which would have accompanied a cremation burial, was found in a small area of soil between the original BT cable trench and a close-by electricity cable trench.

"Flagons are likely to have held wine as part of a meal to accompany the dead into the next life," the article explained. Several pieces of other vessels were found as well.

The 550 finds ranged from Mesolithic flint tools to a gold half sovereign from Queen Victoria's reign.

Most came from metal detectorists, but a large number were from people who found things in their gardens, or while out walking.

In the new issue, readers can find out about a possible hoard of coins investigated by volunteers during excavations at West Marden, and the discovery of what may be the original medieval hall of the Bishop's Palace in Chichester.