Lancaster University researchers have produced a Register of British Slave Traders, documenting thousands of people who financed the trade.

The Register records nearly 250 years of trafficking enslaved African people, from the 16th to 19th centuries.

It reveals the involvement of individuals and organisations across Britain, including the British monarchy.

Dr Nicholas Radburn, from Lancaster University’s School for Global Affairs, was co-investigator on the project and discovered evidence of enslaved African people being branded with the symbol of the British crown on the instructions of the South Sea Company board – a British crown-backed enterprise.

Dr Radburn made the discovery while looking through the company’s archives at the British Library. He said: “I stumbled upon this chilling image as I leafed through the papers of the South Sea Company in London. Among the litany of detail on the company’s bloody business of slaving within those papers, this image really stood out. It captures so well the horrid realities of the slave trade, as well as the tight connection between the company and the royal family.”

The Register of British Slave Traders compiles and presents information on all known slave-traders in Britain who invested in the trafficking of captive Africans from 1563 to 1807. The database can be used to find out who financed the British slave trade, where they lived, what legacies they made, which other businesses they were involved with, and which organisations they were connected to.

The Register focuses on the individuals who sought to profit from the enslavement of more than 3 million African men, women, and children, whose identity was - for the most part - erased from the historical record.

Dr Radburn added: “The Register brings into sharp focus the way that the slave trade was woven through this country’s economy and society. It will doubtless become a key research tool for historians who want to interrogate Britain’s slaving past, and the importance of that past for shaping the present.”

A Guardian series entitled ‘Enslaving nation’ introduces the findings of this four-year project led by researchers from Lancaster University, and involving experts from UCL and the University of Manchester. The project was led by Professor William Pettigrew, formerly of Lancaster University and now at King’s College London, and co-led by Dr Radburn.