Abstract: This thesis employs lead and strontium isotope analysis of teeth by TIMS to identify migrants amongst British archaeological cemetery populations since the Neolithic. The study evaluates the benefits of combining two independent isotope systems with the exposure information obtained from elemental concentrations of lead and strontium. It demonstrates that they provide complementary information about mobility but highlights how their efficacy fluctuates both spatially and temporally in the periods investigated. Strontium was useful in all periods but heavily biased towards maritime 87Sr/86Sr (~O.7092) making it a poor discriminant between coastal habitats where lead was superior. Lead utility changes following the advent of large-scale mining and metallurgy, when anthropogenic ore lead severs the link between geographical origin and lead exposure. A cultural focussing of British enamel signatures ensues accompanied by a concomitant rise in lead burdens. British lead exposure during the last two millennia appears more indicative of status and the cultural sphere (e.g. rural/urban) than geographical origin. The results are assessed in the light of migration theory and traditional archaeological and osteological indicators. Samples used are core enamel and co-genetic primary crown dentine, which neither model nor remodel in vivo and thus remain representative of a constrained period of childhood. Modem and archaeological teeth are investigated to assess isotope variability intra-enamel, intra-tissue, intra-antimere, intra-dentition, intra-sibling and between mother/child pairs. Recommendations for future tissue sampling and standardisation are made. The fundamentals of tooth biomineralisation are reviewed and clarified, chiefly that incremental enamel structures relate to initial formation not mineralisation; lead and strontium are principally incorporated during mineralisation. Macromorphological preservation proved no guide to biogenic strontium or lead isotope integrity. Mature, but not immature, enamel proved highly resistant to diagenesis whether well preserved or not. Dentine was highly susceptible to diagenesis irrespective of preservation state and is proposed as a proxy for the time averaged isotope signature of the soil. Moreover, it is argued that lead and strontium behave differently in teeth; uptake mechanisms are different and they respond independently to subsequent migration. Results suggest soil leaches were useful but complex and the most suitable leach reagent may be specific to the soil type and isotope system. Two Norse Period immigrants (male and female) were identified at Cnip, Lewis; the the 87Sr/86Sr signatures constrain their origin to Tertiary volcanics. In the North Atlantic these occur on Iceland, Faeroe Isles, and Antrim in Ireland but not Norway. No indubitable immigrants were identified at the Anglian cemetery at West Heslerton, Yorkshire but soil leaches and juveniles suggested a local 87 Sr/86Sr signature range. "Non-locals" included both sexes, weapon burials and unaccompanied burials, providing no evidence for an immigrant group composed solely of male warriors. All analysed burials with wristclasps and cruciform brooches were non-local, supporting Hines' (1984) hypothesis that wristclasps confirm the presence of Norwegian immigrants during this period.