A Roman wall discovered at the Gozo Cathedral, in Victoria when workers knocked down another wall underneath the sacristy must be covered up again, according to a Malta Planning and Environment Authority enforcement notice, because the work was not approved.

The episode is the latest in a series of disputes between the parish priest, Mgr John Vella Gauci, and the authority over construction work at the cathedral.

The Roman wall was unearthed when workers knocked down a 100-year-old wall in a room underneath the sacristy. The parish priest had an inkling that the finding was of historical value and called George Azzopardi, who represents Heritage Malta in Gozo.

Mr Azzopardi confirmed the find and began to supervise the work after he was commissioned by the Superintendency.

"There have been various interventions at the cathedral over time and the other wall was practically touching it. There are 12 visible courses in this Roman wall and I have never come across a documented wall in Gozo this high," Mr Azzopardi said.

He said the stones had been interfered with at some point, and were even covered in plaster when discovered, but they were original and in their original position.

Slabs that were inserted much later into the Roman wall and used as a staircase to the sacristy were also removed.

The room under the sacristy where the ancient wall was found has been occupied in living memory by one the cathedral's sacristans and then a priest. The parish priest is expanding the room because the existing sacristy has become too small.

However, the authority issued a stop and enforcement notice on November 28 because the work had been carried out without permission.

When asked to explain why it had done this when a Roman wall had been discovered, a spokesman for Mepa said: "The enforcement notice was served to the parish priest to safeguard archaeological remains... A full permit application outlining the methodology to be used to preserve this historical heritage is needed before further works can continue".

However, the authority's own stop and enforcement notice issued on November 28 is unequivocal, specifying that the land "must be restored to its condition before the development took place" within 16 days. Complying with this would inevitably involve reconstructing the wall which rested against the ancient structure.

Mr Azzopardi said that three floors, practically joined together, had been found towards the bottom of the Roman wall, built at different times, as well as a man-made depression which had been filled with coins and broken pottery, some of which were prehistoric. The pottery consists of imported as well as locally made items and the most recent is mediaeval.

He said: "Everything has been documented to describe the layers, sequence of layers as well as what was found and I have also been monitoring the workmen. Boxes have been labelled and I am preparing a report which, I hope, will be ready by the end of the year.

"Apart from that everything down here has been disturbed before and I think that the worst interventions took place in the 19th century."

Mgr Vella Gauci expressed his dismay, saying he had taken every step to document and preserve the ancient wall at the cathedral which had gone for many years unnoticed.