This small-scale study focuses on variation in the relative marker paradigm in the vernacular of a group of preadolescents recorded in the Greater London area. The distributional and multivariate analyses of variation in relative marker usage in restrictive relative clauses reveal that the wh-forms who and what are well-established in the relative marker paradigm of the preadolescents. Who and what are shown to be sensitive to the animacy of their antecedent heads: Who is strongly favoured by human antecedents, whereas what is preferred with non-human antecedents. The numerically dominant relativizer that is shown to be strongly conditioned by the grammatical function of the relative marker as well as being favoured by indefinite and inanimate antecedent heads. The zero variant is similarly sensitive to syntactic function, and is preferentially selected in non-subject position. Furthermore, the selection of zero relatives is found to be highly constrained by clause length. Cross-variety comparison of the results with previous research on other English dialects suggests that not only are there nuanced differences in the choice of relative marker, but that there are possibly construction-specific differences constraining the choice of specific variants.