This oversized set is rare for several reasons. First, the pattern is very rare. It is called "Drunken Chinaman" in the Mason's Collector's Club 2013 compendium of patterns. Second, the form is rare: breakfast cups were not ordered with every tea set, and are much less commonly found than tea and coffee cups. Third, it was rare for Mason's to number their patterns during this period (c 1835). This set is numbered 466 in red.
The set is in excellent condition. There are no chips, no cracks, and no repairs. The gilding at the edges of saucer and cup is 95% intact. Both pieces ring when tapped. There is some slight discoloration in the bottom of the cup's interior, and crazing on the base. The cup is 2-3/4" high, with a diam. of 4-1/2". The saucer's diam. is 6-3/4".
Marked in black: MASON'S PATENT IRONSTONE CHINA with crown and banner.