In recent years, the dynamics of poverty and unemployment have come under i
ncreasing scrutiny, but another of the risks with which the welfare state c
oncerns itself - disability - is still largely understood only in a static
sense. This article uses longitudinal data from the British Household Panel
Survey to investigate the complexity behind a cross-sectional snapshot. Fi
rst, a breakdown is given of the working-age population who are disabled at
any one time by the 'disability trajectories' they follow over a seven-yea
r period. Second, the expected duration of disability for those who become
disabled during working life is examined. The results show that only a smal
l proportion of working-age people who experience disability are long-term
disabled, although at any one time, long-term disabled people make up a hig
h proportion of all disabled people. Over half of those who become limited
in activities of daily living as adults have spells lasting less than two y
ears, but few who remain disabled after four years recover, Intermittent pa
tterns of disability, particularly due to mental illness, are common. Faili
ng to distinguish the different disability trajectories people follow has l
ed to policies which marginalise disabled people and are costly to the stat
e.