A Roman mosaic unique in Britain depicting one of the most famous battles of the Trojan War has been uncovered in a farmer’s field.

The artwork was discovered during excavations of an elaborate villa complex made up of a host of structures and other buildings, dating to the third or fourth century AD, Historic England said.

Such is its rarity and importance, the site has been officially protected as a scheduled monument by the Department for Digital, Culture, Media and Sport (DCMS), it was announced on Thursday.

The mosaic depicts a scene from Homer’s The Iliad – about the epic fight between Achilles and the Trojan hero, Hector.

It is one of only a handful of such mosaics in Europe, and was part of the floor of a large entertaining or dining area within the villa.

The complex is likely to have been occupied by a wealthy individual from the late Roman period.

Duncan Wilson, Historic England’s chief executive, described the find as “remarkable”.

The site, in Rutland, was discovered during last year’s lockdown by Jim Irvine, whose father Brian Naylor owns the land.

Mr Irvine then notified the authorities, leading to an excavation by University of Leicester archaeological services (ULAS).

He described how what started as “a ramble through the fields with the family” led to the “incredible discovery”.

“Finding some unusual pottery amongst the wheat piqued my interest and prompted some further investigative work,” he said.

“Later, looking at the satellite imagery I spotted a very clear crop mark, as if someone had drawn on my computer screen with a piece of chalk.

“This really was the ‘oh wow’ moment.”

Archaeologists later discovered remains of the mosaic, measuring 11m (36ft) by almost 7m (22.9ft).

It is unique in the UK in featuring two heroes of antiquity, Achilles and Hector, and their battle which ultimately ended in Hector’s death.

John Thomas, of ULAS, said it was “the most exciting Roman mosaic discovery in the UK in the last century”, and a “very well-preserved example of a villa in its entirety”.

He added that the person who commissioned the artwork clearly had “a knowledge of the classics… who had the money to commission a piece of such detail”.

Other buildings and features revealed by site surveys include what appear to be aisled barns, circular structures and a possible bath house, all within a series of boundary ditches.

Fire damage and breaks in the mosaic, suggests later reuse of the site after it fell into disuse.

Human remains were also discovered in the rubble covering the mosaic and are thought to have been interred after the building was no longer occupied.

The age of the remains, though later than the mosaic, are currently unknown but suggests that some time in the very late Roman or early Medieval era the villa had a repurposed use.

Evidence recovered from the site will be analysed by the UK’s foremost expert on mosaic research, Dr David Neal, and others.

The protection as a scheduled monument recognises the exceptional national importance of the site, ensuring it is protected from practices like illegal metal detecting.

The dig, on private land, has now been back-filled to protect the site and work will continue to potentially turn over the field to grassland to lower the risk of future damage from ploughing.

Heritage Minister Nigel Huddleston said: “This fascinating discovery of an elaborate Roman complex in Rutland is helping us to understand more about our history.

“I’m delighted we have protected this site to help further studies and excavations.”

The discovery of the Rutland villa and filming as the mosaic is uncovered will be featured as part of BBC Two’s Digging For Britain in early 2022.