An excavation is about to start at one of the most important Roman villas in Western Europe. Its spectacular mosaics were saved by readers of The Times five years ago after being placed on the World Monuments Fund’s list of the most endangered sites.

One of Britain’s leading archaeologists is to explore the 1.6hectare (4acre) site around Brading Roman Villa on the Isle of Wight. Barely 15 per cent of it has been excavated and the dig is expected to last five years.

Sir Barry Cunliffe, Emeritus Professor of European Archaeology at Oxford University, said that the north side appeared to suggest a large assembly hall with side aisles.

The finds could include mosaics, although it is unlikely that they would match the quality of those within the villa itself with their depictions of peacocks signifying eternal life, Orpheus charming the beasts of the forest and Tritons, or sea deities, carrying reclining nymphs on their backs.

In 2003 readers of The Times responded to warnings that the mosaics would have to be reburied and removed from public view unless money could be raised to rehouse them. Their protective corrugated-iron structure had been condemned after flood waters in a heavy storm inflicted serious damage a decade earlier. Readers contributed more than £100,000 to the cause, enabling the construction of a £3.1 million single-storey grass-roofed building, which was opened in 2005 and has won international awards. Kenneth Hicks, a trustee of the charitable trust that owns the villa, said: “ The Times was the catalyst that meant the project was a success.”

The Romano-British settlement on the island flourished through an active stone-quarrying industry and maritime trade. The villa’s remains disappeared from sight until 1879, when a local farmer stumbled across them.

Sir Barry said that the excavation could give an insight into the identity of the owner of the villa. Its luxury suggests that it was owned by the wealthiest of Roman Britons. The sophistication of the mosaics – which are replete with allegory, politics and double entendre – suggest someone highly cultured. One theory is that the villa belonged to Allectus, who ruled Britain in AD293296 after murdering his predecessor Carausius, an army commander who had proclaimed himself emperor of Britain.

The excavation, which is due to start in August, will include up to 20 graduate archaeologists and also involve local people, particularly the young. The trust needs £50,000 a year to make that possible and has launched an urgent appeal for help.