by Sam Lennon and Jovas Martinkus

An Ancient Roman coin showing an emperor who murdered his way to power has been found by a treasure hunter.

The find of the gold coin near Dover, called an Aureus, shows Allectus, a finance minister who rose to the top by killing his predecessor.

It will be put up for auction in London by currency, medals and jewellery specialists Dix Noonan Webb and could sell for as much as £100,000.

Christopher Webb, coin department head, said: “This is a unique opportunity to acquire a stunning and extremely rare Aureus. It is only the second found in Kent, and is the first to be sold at auction.

"We are extremely pleased to be selling this coin that despite its age, it has the original colour and only a few tiny marks and minor scrapes.

"There are only 24 Aurei of Allectus known. This coin is a die match to one in the British Museum."

The 3rd Century coin was found near a newly-ploughed field last month.

The discovery, near a Roman road, was by a 30-year-old metal detectorist who wishes to remain anonymous.

He says: "After 45 minutes I found the coin. I still can’t really believe what I discovered.

"It is my greatest find by miles – I initially thought it was a half sovereign, but I gently sprayed it and it started to gleam.

"It appears to be the first Allectus gold coin reported as being found in over 50 years."

The finder had it authenticated after taking it to the British Museum.

The Aureus will go under the hammer at Dix Noonan Webb's auction rooms in Bolton Street in London's Mayfair on June 12.

It is estimated to fetch £70,000 to £100,000.

It is 4.31 grammes and only bigger than a modern 1p.

One side shows the emperor's head and the other has the god Apollo with two captives.

Allectus was the finance minister for the emperor Carausius who controlled both Britain and Gaul (now France and neighbouring countries such as Belgium and Luxembourg).

Allectus seized power by assassinating Carausius in AD 293 but died in battle in 296.

The coins showing Allectus would only have been legal tender during his three years in power.

Deal has long been presumed to be the place were the invading Romans, led by Julius Caesar, first landed in Britain, in 55BC.

But in 2017 archaeologists argued that there was new evidence to show they had actually arrived at Pegwell Bay.

The Romans' name for Dover was Dubris and the most distinct reminder of their presence in the town is the Roman Painted House in New Street.

English Heritage also preserves a Roman fort in Sandwich.