Gorgeous bangle was designed by Kenneth Jay Lane exclusively for Royal Worcester in the mid-1970's. The bangle itself is signed "Fine Bone China," "England," and "Royal Worcester." The bangles were also signed with hang tags that were signed "Kenneth Jay Lane Limited Edition." In his book Faking It, Mr. Lane describes similar pieces, including necklaces, that were made by Royal Worcester; these can be seen on page 48 in the book.
Condition is fine with no issues; note that across from the signature, there is a small hole from the manufacturing process. The inside measurement is just over 2 1/2 inches in diameter. Despite being made of china, the bangle is quite substantial and can be worn without worrying about it chipping or breaking. However, I wouldn't recommend dropping it!