Today, the Britannia Two-Pound Coin remembers the fire that burned the interior of the New Royal Mint 201 years ago.
First, a brief article in The Gentleman’s Magazine, 1815 described the fire:
Tuesday. Oct. 31. 
This morning, between nine and ten, an alarming fire was discovered in the works at the Mint.
The flames were first seen to issue from the Shaking-machine room, on the South of the building.
They soon communicated to the Gold-room, from thence to some counting-houses, and eventually to the Silver or rolling-room, on the Eastern side; and in a short time the Eastern and Southern wings of the building were completely unroofed, and the interior totally destroyed.
In these were contained the great machinery of the works, including the 10, 15, and 30 horse power engines.
During the fire, several ingots were taken from the ruins red-hot; and there was also discovered in one of the rooms, where the fire had been got under, nearly a ton and a half of copper in stivers, half stivers, &c. which had not been much damaged.
The loss sustained by this calamity, including all the implements, machinery, &c. is estimated to amount to at least 60 to 80,000 pounds.
The entire of the magnificent pile in front of the manufactory, remains uninjured.
Next, London, Past and Present, Its History, Associations, and Traditions by Henry Benjamin Wheatley, published in 1891 gave more details about the operations of the facility several years later:
Mint (The Royal), on Tower Hill.
The work of coinage, which had been carried on for many centuries in the Tower of London, was removed here in 18 10.
The coinage of the United Kingdom and of most of our Colonies is executed within these walls.
The present building was designed by Mr. John Johnson, and the entrances, etc., by Sir Robert Smirke, who finished the works.
The facade towards Tower Hill, Graeco-Roman in character, comprises a centre with six columns and pediment, and two wings each with pilasters, on a rustic basement.
The building is imposing from its extent, solidity and simplicity of style.
New machinery was introduced into the Mint, and the operative department was reconstructed in 1881-1882.
The article on the Mint in the last edition of the Encyclopedia Britannia by Prof. C. Roberts-Austen, F.R.S., Chemist to the Mint, contains a plan of this building as thus rearranged.
The various processes connected with coining, after the metal has been brought to the proper standard and cast in ingots of uniform size and thickness, are carried on by a series of ingenious machines in rooms known as the rolling-room, the cutting-out and milling room, the annealing-room, the coining press-room, etc.
An interesting machine is that called “the draw-bench,” by which the metal is drawn through fixed blocks to the precise thickness required for the coin which is to be cut out of it.
In the case of gold the difference of a hair’s breadth in any part of the plate or sheet of gold would alter the weight of a sovereign.
By another machine circular disks are punched out of the sheets of metal of any size required, and by a number of presses these blanks as they are called are stamped on obverse and reverse at the same time.
The force with which the blow is struck; the rapid motion by which sixty or more coins may be struck in a minute; the mode in which the press feeds itself with the blanks to be coined, and, when struck, removes them from between the dies, is very interesting.
A matrix in intaglio is first cut in soft steel by the Engraver to the Mint.
When this is hardened, many dies may be obtained from it, provided the metal resists the great force required to obtain an impression from it.
To prevent the metal of the blank squeezing out in the process of coining, the die is fitted with a steel collar of the exact size of the blank.
The inside of this collar is cut into fine grooves, into which, in stamping, the edge of the metal is forced, and the milled edge of our coins is thus produced.
The blanks are supplied to the press by a feeder, and as they leave the die are pushed by a slide into a receiver.
The gold and silver coins are all weighed by ingenious automatic weighing machines similar to those in use in the Bank of England.
No gold or silver coins are issued from the Mint until a sample of them has been assayed.
When that process has been gone through, other samples are placed in a pyx or casket secured with locks, which require several keys to open, these keys being kept by different officials.
The coins so secured are annually submitted to what is termed the Trial of the Pyx.
This is now performed by a jury of ten practical goldsmiths and assayers, who assay and compare with the trial plates, which were formerly kept in the ancient treasury in the cloisters of Westminster Abbey, the keys of which and of the pyx in which the trial plates were deposited were in the custody of the Chancellor of the Exchequer and the Lords of the Treasury.
The Trial plates are now in the custody of the Board of Trade.
In this trial an extremely small amount of inaccuracy both as to weight and fineness is allowed, but in every instance hitherto the coins have been found well within this remedy, as it is called, and the jury, through the Queen’s Remembrancer, have pronounced a verdict of acquittal.
The gold coin in circulation in Great Britain is estimated at £100,000,000.
Within the Mint is a collection of early matrices for coins, and coins which the coin collector should exert his interest to see.
In 1817 the old office of Warden of the Mint was abolished.
The office of Master of the Mint was virtually abolished by Act of Parliament in 1870, being transferred to the Chancellor of the Exchequer, who is Master of the Mint, ex officio, but without a special salary.
The working head is called Deputy Master, who has to present an annual report to the Treasury.
The office of Master of the Mint was usually given to a political partisan, but in a few instances to eminent men of science — Sir Isaac Newton, Sir John Herschel, and Thomas Graham being conspicuous examples.
A remarkable robbery occurred at the Mint in 1798, when a man of the name of Turnbull entered with a loaded pistol, served himself with 2804 guineas, and then made the best of his way off.
On October 31, 1815, a fire broke out in what was called the shaking- machine room, which caused much destruction.
Another view From Walks Through London, Including Westminster and the Borough of Southwark, with the Surrounding Suburbs … Forming a Complete Guide to the British Metropolis by David Hughson and William Hamilton Reid, published in 1817 gave insights into the building:
The New Mint.–Near the west end of Rosemary Lane is King-Street, leading to the New Mint, erected on the site of the Victualling-Office, before it was removed to Deptford.
The present structure is from a design of Mr. Smirke, Junior, for the various purposes of coinage, and is upon an extensive plan, as it contains every department necessary for the different operations in coining, and residences for the principal officers.
The building is composed of a long stone front, consisting of three stories, surmounted by a handsome balustrade.
The wings are decorated with pilasters; the centre with demi-columns, and a pediment ornamented with the arms of the United Kingdom.
Over the porch is a gallery, balustrades, &c. of the Doric order.
A fire which broke out here in the summer of 1815 did considerable damage in the interior, but happily did not injure the appearance of this beautiful edifice.
By way of contrast, it may be observed, that on this spot once stood East Minster, or the abbey of St. Mary of the Graces, founded by Edward the Third in 1349, in consequence of a fright at sea, on his return from France, when he vowed if he got safe on shore he would found a monastery to the honour of God and the Lady of Grace, if she would grant him the grace of coming on shore.
This foundation was to rival Westminster, but it did not succeed, though it continued till the dissolution by Henry the Eighth.
Previously to the building of the New Mint, the old Victualling Office here had been converted into warehouses for tobacco.
The Britannia Two-Pound Coin shows with an image of the New Mint found in the book From Walks Through London.