A hoard of 11th century coins has been unearthed at a nuclear plant construction site, which could provide rare insight into a turbulent period of English history.

An extraordinary hoard of 11th century coins, unearthed at the Sizewell C nuclear plant construction site, could provide rare insight into a turbulent period of English history, archaeologists have said.

Oxford Cotswold Archaeology (OCA) discovered more than 300 silver pieces at the site on the Suffolk coast, near Leiston.

The find could provide valuable insight into the social and political upheaval of the last decades of the Anglo-Saxon period.

This includes further evidence that a regime change following the coronation of Edward the Confessor in 1042 caused ‘great uncertainty’ among the population, the OCA said.

In total, 321 coins, minted between 1036 and 1044, were found in a bundle of cloth and lead and are speculated to have been the savings of a local figure ‘of middling status’.

Andrew Pegg, an archaeologist at OCA, was the one who discovered the coins – describing the breakthrough as a ‘privilege to find’.

Mr Pegg said: “I was shaking when I first unearthed it, seeing a single coin edge peeking at me. A perfect archaeological time capsule.

“The information we are learning from it is stunning and I’m so proud to have added to the history of my own little part of Suffolk.”

All the coins found date to the reigns of Harold I, Harthacnut, and Edward the Confessor.

While most were minted in London, many were struck at other locations, including Thetford, Norwich, Ipswich, Lincoln and Stamford.

Others came from smaller mints, such as Langport and Axbridge, in Somerset.

The hoard has been nicknamed ‘the pasty’ due to it being roughly the size of a Cornish pasty.

Alexander Bliss, a coin specialist at OCA, said: “This new coin hoard provides us with valuable insight into the rich historical backdrop of this period, adding to the evidence that Edward the Confessor’s accession to the English throne was marked by a degree of uncertainty and concern within wider society.

“Analysing this new coin hoard has been a wholly collaborative effort, involving valuable input from multiple specialists and project partners in the fields of numismatics, finds and conservation.

“To play a small part in bringing its story to life has been an honour and a privilege.”

The OCA described the mid-11th century as a turbulent period in English history, with shifting allegiances.

Following over 25 years of rule by first the Danish king Cnut and then his sons Harold and Harthacnut, Edward the Confessor was crowned in 1042, restoring the House of Wessex to the throne.

The OCA said wealthier people associated with the previous regime were exiled or had their property confiscated – and have speculated that the owner of the hoard may have buried the coins as a precaution.

The reason why the coins were never dug up may never be understood with certainty.

The owner may have died, been prevented from returning to the spot they were buried, or been unable to pin point exactly where they were hidden.

Damian Leydon, site delivery director at Sizewell C, said archaeology was a ‘significant part’ of the construction of the plant, helping the developers learn what lies beneath the earth before building begins.

He described the hoard as an extraordinary find.

OCA and Sizewell C plan to make the discoveries public as soon as possible.

Mr Leydon added: “This project provides a rare and fascinating glimpse into Suffolk’s rich history, deepening our understanding of this part of Britain.”

The new discovery is set to feature on the new season of the BBC’s Digging For Britain today.