ɪn nˈaɪntiːnhˈʌndɹɪd sˈɪksti sˈɛvən, ðɛɹwˌɜː sˈɛvɹəl lˈaɪnˌʌp tʃˈeɪndʒᵻz, ɹɪzˈʌltɪŋ ɪnðə bˈænd wɪð ˈiːən "slˈʌdʒ" lˈiːz ˌɔn vˈoʊkəlz, mˈɛl ɡˈæli ænd ˈælən klˈiː ˌɔn lˈiːd ɡɪtˈɑːɹz, fˈɪl ˌoʊvɚfˈiːld ˌɔn bˈeɪs ænd dˈeɪvɪd wˈɪljəmz ˌɔn dɹˈʌmz.
In 1967, there were several line-up changes, resulting in the band with Ian "Sludge" Lees on vocals, Mel Galley and Alan Clee on lead guitars, Phil Overfield on bass and David Williams on drums.