Wikipedia says -
" The trio formed in 1960, when Mary "Dusty" O’Brien, who had been a member of all-girl singing trio The Lana Sisters, joined her brother Dion O'Brien and Tim Feild, who had been working as a duo, "The Kensington Squares". Dion became Tom Springfield, and Mary became Dusty Springfield.
Tom Springfield was a songwriter and arranger with a wide knowledge of folk music and the group had strong vocal harmonies as well as Dusty’s powerful lead. Occupying a musical sphere comparable to that of the contemporary Peter, Paul and Mary they were signed to Philips Records and released their first single, "Dear John," in 1961, followed by two UK chart hits with "Breakaway" and "Bambino" – like their other records, produced by Johnny Franz.
The first recording contract the Springfields signed was offered by producer Johnny Franz at Philips Records in London. With early singles including "Breakaway" and "Bambino", and numerous television appearances, the trio soon became very popular in the UK. After Feild was replaced by Mike Hurst the Springfields became even more successful. In 1962, their version of "Silver Threads and Golden Needles" reached the US Top 20 (Billboard), #23 (Cash Box), the first single by a British group ever to do so (predating the Tornados’ “Telstar” by two months, and The Beatles by 15 months). The record also reached #1 in Australia. It featured lead guitar by Judd Proctor. "Silver Threads and Golden Needles" sold over one million copies, and was awarded a gold disc.
"Island of Dreams" rose to the UK #5 at the beginning of 1963, and stayed in the charts for six months. The follow-up, "Say I Won’t Be There", was also #5 in the UK Singles Chart. By this time, the Springfields were one of the most popular groups in the UK. The group had several chart hits and had recorded several foreign language records. However, Dusty Springfield felt limited by the group's folk act and Tom's lead role within the trio and, towards the end of 1963, decided to leave for a solo career, at which point the group disbanded."The Spring fields - Side one The Springfields - Side two