This cache is within the pleasant backstreets of Marylebone, London, about 10 minutes walk from either Marylebone, Baker Street or Marble Arch stations. It is a small magnetic tube of about 5cm containing a log that may require some tweezer dexterity to remove! No pen supplied, and please replace the cache exactly how found, thank you.
And now a short biography. Most will be familiar with the name William Pitt (both younger & elder): eminent British polititians etc etc.
Well how about another, namely William Pitt Byrne. Named after W.P. the Younger, he was born in 1806, and achieved fame as a newspaper editor and proprietor of The Morning Post. Broadening the paper's focus from being a mostly political journal by including more general topics, he ended his connection prior to his death to follow literary pursuits, contributing to leading journals.

After his death in 1861, his wife and friends built a memorial fountain in his name at the south end of Bryanston Square, nearby to his former residence in Montague Street. Still in existence, it is a Grade II listed monument which has an associated plaque containing very typically overblown and bombastic Victorian language!
Enjoy the find, and for the eagle-eyed there is a rivet and cut benchmark to be found very close by too!