dˈʊɹɹɪŋ ðə nˈaɪntiːnhˈʌndɹɪd sˈɛvənti z splˈɪt bᵻtwˌiːn kɹˈɑːslɐndˌaɪt ænd dʒˈɛŋkɪnsˌaɪt sˈoʊʃəl dˈɛməkɹˌæts wɪðˌɪn ðə lˈeɪbɚ pˈɑːɹɾi, mˈɑːɹkwænd wʌz pˈɑːɹt ʌvðə dʒˈɛŋkɪnz ɡɹˈuːp ænd dʒˈɔɪnd ðə sˈoʊʃəl dˌɛməkɹˈæɾɪk pˈɑːɹɾi ˌɛsdˌiːpˈiː wɛn ɪt wʌz fˈaʊndᵻd.
During the 1970s split between 'Croslandite' and 'Jenkinsite' social democrats within the Labour Party, Marquand was part of the Jenkins group and joined the Social Democratic Party (SDP) when it was founded.