Harold Shipman is generally considered to be Britain’s worst serial killer, with more than 250 murders ascribed to his name. But hidden among the tales of habitual drunks, petty thieves and small-time fraudsters published online last week sits the file of a little-known Bristol-born woman who may well have killed more.

While largely forgotten today, Amelia Dyer’s crimes paved the way for one of the most sensational trials of the Victorian era – and spotlighted the pandemic problem of infanticide in 19th century Britain. Her Prison Commission file, now visible online, logs Dyer’s final moments on the scaffold at Newgate Gaol on June 10, 1896, and records her hanging with characteristic Victorian efficiency: “On account of her weight and the softness of the textures, rather a short drop was given. It proved to be quite sufficient.”

Three weeks earlier, Dyer had been convicted at the Old Bailey of the murder of two babies. They had been strangled with white tape, wrapped in parcel paper and dumped in a carpet bag in the River Thames at Reading. She became a household name, ballad-mongers even wrote songs about her; her case raised the profile of the fledgling NSPCC and even firmed up our adoption and child protection laws. Yet within a few decades, her criminal career was all but forgotten.

Reading police had been alerted to Dyer back in April by the discovery of another tiny infant in the reeds of the Thames. An address on the parcel paper led the police to a stout midwife described variously as “motherly” and “homely”. What they discovered inside Dyer’s two-up-two-down, rented terraced house on Kensington Road was damning.

Her home was crammed with evidence of a hefty trade in infant life – dozens of vaccination papers, vast quantities of tiny clothes and countless pawn tickets for baby clothes. Letters and receipts for newspaper advertisements arranging adoptions were also recovered, indicating that Dyer was operating under several aliases, including Harding and Smith. The most gruesome evidence was the heavy stench of rotting flesh coming from the kitchen pantry and from a trunk under her bed. The police were in little doubt that they had uncovered a baby farm. They ordered an immediate dragging operation, watched by crowds of onlookers lining the river banks, drawn by lurid press coverage. When the body count rose to 50, Amelia told police: “You’ll know all mine by the tape around their necks”.

As the police investigation grew, so did the efforts of investigative journalists. It became clear that Dyer had profited from her trade for almost 30 years, travelling as far afield as Liverpool and Plymouth.

Dyer first opened a house of confinement in the Bristol suburb of Totterdown in the late 1860s, and charged a fee to take in unmarried women when they could no longer hide their pregnancies. Some asked for their infants to be stifled at the moment of birth, since Victorian coroners were unable to distinguish between suffocation and still-birth.

Dyer also fostered infants for a weekly fee, maximizing her profits by slowly starving her little charges, muting them with daily doses of the liquid opiate, laudanum, known colloquially as “the quietness” because it stifled both a baby’s appetite and its cries.

Ten years later, having completed a six-month prison sentence for infant neglect, Dyer changed her modus operandi. No longer would her house be filled with emaciating infants. Now she accepted only full adoption in exchange for a lucrative one-off payment. She silenced the infants within hours, using a length of white tape tied twice around their necks and dumped their bodies in rivers or buried them in the gardens of her rented lodgings.

The world which enabled this wholesale trade in infant life may seem entirely alien today, but its scars are remarkably recent. Our Dickensian vision of Victorian urban filth is missing one grim detail: the bodies of dead infants littered the streets of British cities and reports of their discovery were too commonplace to be considered newsworthy.

Endemic infanticide was a direct consequence of mid-century legislation designed to deter illegitimacy; far from fixing the problem, the removal of all financial obligation from fathers merely condemned unmarried mothers to an impossible situation. Forced out of employment and barred from the workhouse, a single mother could either prostitute herself, starve, or else “make an angel” of her baby. Baby farmers offered a last hope for a desperate minority, but in reality few women were truly blind to the reality of their offspring’s fate once they had been farmed out.

The true scale of Dyer’s crime is almost certainly beyond calculation. At her most frenzied, eyewitnesses reported seeing as many as six babies a day coming into her home. Reading police found evidence of at least 20 children who had been entrusted to her care in the two months before her arrest. Even a conservative estimate of 10 infant deaths a year creates a staggering 300 murders over a 30-year period.

Dyer was by no means the only British baby farmer but she was certainly the most prolific, serving a grim need that society was loath to acknowledge and has been quick to forget.

‘Amelia Dyer: Angel Maker’ is written by Alison Rattle and Allison Vale. http://amzn.to/VT2bqr

Serial killers: Britain’s worst

Dr Harold Shipman Victims: more than 250

The UK’s most prolific murderer was found guilty of 15 murders in 2000 while working as a doctor in Hyde, Manchester. An official report said he killed between 215 and 260 people over 23 years while working in Hyde and Todmorden, Yorkshire.

Mary Ann Cotton Victims: 21

Born in County Durham in October 1832, she was executed in 1873 for murdering her seven-year-old stepson, but was believed to have murdered up to 21 people, mainly by arsenic poisoning.

Dennis Nilsen Victims: 16

The “Muswell Hill Murderer” confessed to killing at least 15 men at his north London flat between 1978 and 1983. After having sex with them, he dissected them and burned their remains or flushed them down the lavatory.

Peter Sutcliffe Victims: 13

Sutcliffe, aka the Yorkshire Ripper, preyed on women – many of them prostitutes in Leeds and Bradford – in the 1970s. He was convicted of murdering 13 and trying to kill seven others. He claimed messages from God drove him to murder.

Fred West Victims: 11

West, working alone and later with the help of his wife, Rosemary, tortured, raped and murdered at least 11 women and girls between 1973 and 1979. He committed suicide while in police custody in 1995. She was later convicted of nine murders, including that of her daughter and Fred’s stepdaughter.

Peter Manuel Victims: 8 (perhaps 15-18)

The American-born Manuel was convicted of eight murders in southern Scotland between 1956 and 1958. He later admitted to killing 18 people though the true figure is believed to be 15.

John Christie Victims: at least 8