To slightly interested outsiders, the survival of the probation service under four successive Conservative governments might be a little surprising. A working practice based essentially (at least in the public mind) on social casework appeared at odds with the tough law and order rhetoric of Margaret Thatcher. Yet more interested and informed observers would know that the feat of survival was perhaps not so surprising. Publicly tough measures were accompanied by a need to keep public expenditure costs down - even in the field of law and order. The probation service was to be a key agency in delivering the `alternative' to custody, an increasingly demanding punishment in the community. This necessitated significant change in the management and practice of the probation service, yet at the end of those four Conservative governments, the probation service was still relatively intact, recognizable to those who had known it for a long period of time. This article will focus on the changes since the election of a Labour government in 1997, changes which in many ways are far more radical than anything envisaged by the Conservatives. An argument will be presented which suggests that the ground for such far-reaching changes was cleared by previous Governments, but that it was the advent of the public protection agenda in its most recent incarnation which has facilitated what has been termed here the `deconstruction of the probation service'.