From Pages 50-60 The Life of Mark Twain - The Middle Years 1871-1891:
Sam reminisced in his autobiography that in the late summer of 1872, “I took a sudden notion to go to England and get materials for a book about that not-sufficiently known country, It was my purpose to spy out the land in a very private way and complete my visit without making any acquaintances. I had never been in England, I was eager to see it, and I promised myself an interesting time. He landed at Queenstown on August 30, at Liverpool the next day, and he registered at the historic Langham Hotel at Portland Place in London ...
From The Twainian Vol 36 No 2 (1977):
“With Livy and the infant Susy in good health after a quiet summer at the shore, Mark Twain sailed for England on August 21, 1872. The purpose of the trip was threefold: to protect “Roughing It” against the notorious British pirate John Camden Hotten and other literary freebooters, to give lectures in London, and to collect notes (sent to Livy in the form of a journal) for a book on England and the English which Mark never got around to writing.” He writes Olivia on August 29/72 from shipboard, saying in part: “I have given the purser a ten-dollar telegram of 3 words to send to you from Queenstown, & also my journal in 2 envelopes...” He again writes to Olivia on September 11, 1872 from The Broadway, Ludgate, London, E.C. saying in part: “Have not even written in my journal for 4 days - don't get time. Real pleasant people here.”
Our unpublished pages of the letter, which Mark calls his “journal” has been dated September 16, 1872. In “Mark Twain's Letters,” Harper, 1917 on page 198 Paine says: “He was treated so well and enjoyed it all so much that he could not write a book - the kind of book he had planned. One could not poke fun at a country or a people that had welcomed him with open arms. He had made plenty of notes, at first, but presently gave up the book idea and devoted himself altogether to having a good time.”
“There was once an American thief who fled his country & took refuge in England, & he dressed himself after the fashion of the Londoners & taught his tongue the peculiarities of the London pronounciation and did his best in all ways to pass himself for a native - but he did two fatal things: he stopped at the Langham Hotel & the first trip he took was to visit Stratford-on-Avon & the grave of Shakespeare & these things betrayed his nationality.”