This beautiful and functional teapot in the "Old English" shape has been a puzzlement for me...I haven't identified the maker. It dates c 1825.
The teapot is 6-1/2" high. It is in excellent condition. There are no chips, no visible cracks, and no repairs. There is some mild crazing. The cover rings when tapped. The teapot does not ring.
This exact shape and pattern is shown on page 303, plate 1815, of "An Anthology of British Teapots" by Miller and Berthoud. They list it as "Unidentified". Theirs is unmarked. This one has the pattern number 651 hand painted on the base. Three companies making this style of teapot, at this time, with pattern numbers in the 600's are: Rockingham, Machin, and Rathbone.