The mystery of Jack the Ripper’s identity was solved by the Metropolitan Police immediately after his rampage of killings in the East End in 1888, latest research claims.

East London Advertiser: Jack the Ripper's reign of terror on the streets of Whitechapel, 1888. Picture: Docklands MuseumJack the Ripper's reign of terror on the streets of Whitechapel, 1888. Picture: Docklands Museum (Image: Docklands Museum)

Scotland Yard found out who he was after he committed suicide drowning in the Thames and closed the file on the Whitechapel Murders, according to academics.

But the ongoing secrecy theory "to protect his respectable family" fuelled theories down the years naming various suspects like deranged lunatics, craftsmen, surgeons, masons, royalty and even the editor of the East London Advertiser at the time.

Most theories have been dismissed while the Ripper "industry" went global in the 129 years since, even though police could have drawn a line, according to authors Christine Ward-Agius and Jonathan Hainsworth.

East London Advertiser: Fourth vicitm of Jack the Ripper, Catherine Eddowes, discovered in Aldgate at Mitre Square, October 1888. Picture: Illustrated Police NewsFourth vicitm of Jack the Ripper, Catherine Eddowes, discovered in Aldgate at Mitre Square, October 1888. Picture: Illustrated Police News (Image: Illustrated Police News)

The Ripper was "a toff in a top hat, a barrister and Oxford graduate" named Montague John Druitt who was homicidal towards defenceless women, it is claimed.

"Druitt was posthumously disguised as 'a mad surgeon' for public consumption to protect his respectable family," they say in their yet-to-be-published work The Escape of Jack the Ripper.

"This discreet 'gentlemanly sleight-of-hand' by Etonian upper-crust police chief Sir Melville Macnaghten 10 years later fooled most people and has inadvertently bamboozled researchers for 100 years since."

East London Advertiser: Last victim Mary Jane Kelly discovered at Miller's Court in Dorset Street... Did Jack the Ripper commit suicide a month later? Picture: Met Police archiveLast victim Mary Jane Kelly discovered at Miller's Court in Dorset Street... Did Jack the Ripper commit suicide a month later? Picture: Met Police archive (Image: Met Police archive)

Druitt was a medical student who dropped out and later went into law, but led a double life prowling the streets, they believe.

"A blood-stained Druitt was arrested in Whitechapel, but deployed his pedigree as the nephew of a famous physician to bluff his way to freedom," their book claims.

"He later confessed to his clergyman cousin, Charles Druitt, and was hurriedly placed in a lunatic asylum, then had to flee as the police dragnet was closing."

East London Advertiser: Many suspects are arrested... no-one is ever charged with the Whitechapel Murders of 1888. Picture: Metropolitan ArchiveMany suspects are arrested... no-one is ever charged with the Whitechapel Murders of 1888. Picture: Metropolitan Archive (Image: Metropolitan Archive)

Druitt took his own life a month after the last killing, when Mary Kelly's mutilated body was discovered by a rent collector at her lodging in Dorset Street in Spitalfields.

Druitt's corpse was later washed up in the Thames. The shamed Druitt family is said to have alerted Scotland Yard that The Ripper was dead, while desperate to conceal their connection that could ruin them after his suicide.

But his clergyman cousin broke ranks a decade later about the truth of the suicide, which led the police chief to give a different version to quash the troublesome vicar.

The Escape of Jack the Ripper, by Christine Ward-Agius and Jonathan Hainsworth, is being published in the spring by Amberley Publishing.