Historical geographers have located the Irish in Liverpool at the bottom not only of the labour market but also of the residential hierarchy. Given their limited resources, the Irish tended to congregate around ‘corestreets’ in the city's two major working-class areas, close to the docks and the casual labour markets: the ‘instant slum’ of the north end with its purposebuilt court housing, and the failed middle-class suburb of the south end, hastily ‘made down’ into overcrowded and cellared street housing. Over time, there was to be substantial concentration in the north end, extending out from the two pre-Famine ‘clusters’, the eastern half of Exchange and Vauxhall Wards, and behind the docks in Scotland Ward. By contrast, in the south end, where there were original ‘clusters’ between Park Lane and the docks, and between the Custom House and Derby Square, there was less coherence and increased fragmentation, accentuated by a growing Ulster Protestant presence. In the statistical terms of historical demography, these were not Irish ghettos. Outside the ‘scale trap’ of core streets such as Lace Street, Crosbie Street and Marybone (‘as Irish as any part of Dublin’), the index of segregation was not significantly high. The persistence rate was remarkably low (no more than 9 to 18 per cent, Colin Pooley has calculated, remained at the same address from one census to the next) as the Irish, lacking attachment to particular jobs or dwellings, favoured frequent short-distance movements within familiar territory.