Well, now you can see for yourself; I believe this is the only image on the net of the door knocker from the infamous Newgate Prison.
"As black as Newgate's knocker" - The door knocker from the last Newgate Prison
The phrase is defined in Brewer's Dictionary of London Phrase and Fable:
as black as Newgate's knocker Very dark, in colour or character. The simile draws on Newgate Prison's notoriety as a place of death.
He's just another bloody minded old upper-class bugger with a heart as black as Newgate's knocker. Ames Hawes (2005)
This phrase was known by 1880 and remained popular well into the 20th century. Latterly it seems to have been most commonly used by parents chastising children for getting mucky.
For example; H.E. Johnson, writing in 1994 said:
My late mother often used an expression which must have had very old origins. If anything was very dark or dirty — all too frequently referring to myself or my attire — she would refer to it as being, “As black as Newgate’s knocker”.
Related phrases include:
The earlier, As black as Newgate in use between 1820-80 meaning a dark expression or frown or also referring to soiled clothing.
A Newgate knocker was also a Victorian hairstyle popular with costermongers in the 1840s and 50s. It was ‘A lock of hair twisted from the temple back towards the ear’ the resulting ringlet resembling a door knocker.
The original heavy iron knocker which gave rise to these phrases was attached to the main door of Newgate Prison from 1782 until 1902, when the prison was demolished to make way for an enlarged Old Bailey.
Normally the knocker is kept safely locked away inside the Old Bailey. I am very grateful for the rare privilege I had of being able to photograph it and even being kindly permitted to knock it.
The photo was taken in Dead Man's Walk, just outside the Condemned Cell; a part of the Old Bailey that is normally strictly off-limits to visitors. I'll be publishing more images of these grim areas and explaining how I managed to see them in a future post.