Wondering about the name? Well, The Mad Hatter was originally a hat factory called Tress & Co, making hats such as the famous Bowler, Topper and Boater. Hat making dates back to the 15th century in Southwark, but Tress & Co came into existence in the mid 19th century. The building is one of the few original buildings located on Stamford Street, so it really shines when compared to the modern architecture surrounding the hotel in Southwark.
The Mad Hatter, of course, was a character in Lewis Carol's "Alice in Wonderland" which hosts reference to a myth that the glue used in the making of the hat rims contained Mercury. It is said that the Mercury dispersing particles so close to the brain would tamper with the molecules of the mind and therefore send people slightly mad. Thus creating the phrase "mad as a hatter".
Now you know!