My ancestor was a grave robber (and other skeletons in the closet)

The release online of 77 million historical records means that our forebears' lives are just a few clicks away

(Getty Images)

James Cockman was just 16 when he hit on his scheme to add to his meagre income as an apothecary's assistant at a London workhouse in 1776. Aided by two accomplices, he sneaked into the adjoining cemetery and entered the era's nascent trade in stolen corpses by digging up a freshly-interred pauper for sale to medical students learning anatomy.

The only problem for the "highly reprehensible" teenager was that his employers, led by his brother Robert, quickly realised the empty grave was his work and brought him before the local magistrate. In elaborate calligraphy, the fate of Master Cockman was carefully chronicled in the St Marylebone parish records: expulsion from the workhouse, a swingeing £20 fine and imprisonment until it was paid.

Yesterday Philip Richards, a retired civil engineer, found himself revisiting the shady past of his great-great-great-great-uncle after the document outlining his ancestor's crime went online – one of 77 million records covering 500 years of London's history that will eventually be uploaded. The vast collection of parish records, death indexes, land tax files, marriage certificates, school reports, wills and electoral rolls dating from the 16th to the 20th centuries will all be made available, for a fee, on the internet by 2011. The first 250,000 documents from workhouses, which include lists of "lunatics" under the care of the capital's parishes, are already available on Ancestry.co.uk, the American-owned genealogy website.

The database culled from the London Metropolitan Archives and the Guildhall Library Manuscripts in the City offers a unique insight into the lives of millions of ordinary Londoners such as the delinquent Cockman, who was one of the first individuals to be caught dabbling in what became a burgeoning industry in "bodysnatching" cadavers to be dissected by doctors and medical students in late 18th century London.

The gruesome trade was driven by laws which only permitted the bodies of executed criminals to be used for medical science at the height of the Enlightenment. But with only about 50 executions being carried in London every year and a lack of refrigeration meaning that specimens rapidly putrefied, demand for about 500 bodies each year far outstripped supply.

Bodysnatchers such as Cockman became adept at seeking out the freshly-dug shallow graves of paupers. The documents note that Cockman was, "highly suspected of having thrown the body over the wall" of the workhouse in January 1776.

Written in fine copperplate handwriting by Robert Cockman, who was master of the workhouse and later died in penury, possibly brought on by the shame of his brother's conviction, the parish record notes: "James Cockman was legally convicted at the Quarter Sessions for having dug up and carried away the body of a pauper ... and was fined by the court in the sum of £20 and ordered to be imprisoned until such fines were paid."

The scale of the grave-robbing problem only became clear two months later when London's newspapers reported the grisly discovery of the remains of more than 100 bodies in a shed on Tottenham Court Road, where they had been left by suppliers to surgeons and medical schools.

Mr Richards, 73, from Kingston upon Thames, said: "Every family has secrets but we have literally got skeletons in the cupboard.

"We didn't know anything about the workhouse until I began looking into the genealogy of my family. These were hard times and you have to judge what James Cockman did by the standards of the day. It is a fascinating insight into our social history."

It is estimated that about 165 million people worldwide, including half of the UK population, will have an ancestor listed among the 77 million documents, many of which predate the arrival of official censuses and the civil registration of births, deaths and marriages. As well as historical figures such as Oliver Cromwell and the poet and painter William Blake, the documents offer glimpses of the forebears of many current celebrities. It has been established that the Harry Potter author, J K Rowling, is descended from an East End blacksmith and that the pop star Britney Spears' great-grandfather was a sailor from Tottenham in north London.

Josh Hanna, of Ancestry.co.uk, which now has seven billion records online worldwide, said: "No city in modern history other than London can claim to have been the capital of such a far-reaching empire, which is why this collection is of such significance not only to British people but also to many other around the world."

Maybe it's because I'm a Londoner: Famous family secrets

Britney Spears

The US singer's great-grandfather was George Portell, an able seaman in the Royal Navy. At the age of 24, he married Lillian Esther Law, a 25-year-old spinster, in Tottenham, north London, in 1923. George's father was a newsagent and Lillian's father a lighting inspector.

J K Rowling

On 8 December 1872, the Harry Potter author's great-great-great-grandfather, William Richard Rowling, a blacksmith, married Frances Emily Andrews at Mile End in east London. They were both 19. William's father was a moulder and Frances's father was a carpenter.

David Beckham

The footballer's great-great-great-grandparents, John Beckham and Sarah Chandler, married on 4 August 1868.

Patsy Kensit

Thomas Kensit, the actress's great-great-great-grandfather, was baptised in Shoreditch in the East End in 1815.

Charlie Chaplin

The film star was born in Walworth, south London, in 1889. At the age of nine, he entered Renfrew Road workhouse in Lambeth with his family.

Oliver Cromwell

The marriage of the victor of the English Civil War to Elizabeth Bourchier, a leather trader's daughter, took place at St Giles Cripplegate on 13 August 1620. They had nine children.

John Milton

The burial of the author and poet, an official in Cromwell's government, is recorded in 1674 with "consumption" listed as the cause of death.

Samuel Pepys

The diarist was baptised on 3 March 1632 at St Bride's, Fleet Street.