The crippling caseload of social workers prolonged the suffering of a mentally disabled woman - Miss X - who was sexually and physically abused by fellow residents in the house in which she lived, according to a damning report.
The investigation, carried out by social work consultant David Stallard on behalf of the council, found members of staff grappling with up to 120 cases each, with an average of 250 people awaiting allocation to a social worker at any time.
'Waiting lists of this size impose their own stresses and I am not surprised several members of staff described their work as mainly firefighting,' said Mr Stallard.
Borders has now given approval for nine new staff and launched a 13-point action plan, including monitoring of workloads, better guidance on case recording and a review of the guidelines for the protection of vulnerable adults.
Oliver Angus (Lib Dem), portfolio holder for lifelong care, said he was 'confident' the plan would address the problems highlighted in Mr Stallard's report.