More than 20,000 allegations of abuse by care home workers against the elderly and vulnerable have been made in the last three years, figures show.
Of the claims:
12,000 were of neglect
More than 3,000 were of physical abuse
2,400 were of psychological abuse
400 were of sexual abuse
The vast majority related to the care of elderly people in their homes, most aged over 80.
The figures were obtained by a BBC File on 4 investigation under the Freedom of Information Act.
The report revealed how some elderly people were left for days without proper medication or attention to personal hygiene.
Bridget Warr, chief executive of the UK Home Care Association, which represents care companies in the UK, described the findings as "horrifying" and blamed cuts to local Government budgets.
Local Government Ombudsman Michael King said there was a growing problem over standards of home care.
Ombudsman complaints about home care rose by 25% last year to 372 - and 65% of them were upheld.
The Department of Health told File on 4 it has "introduced tougher inspections of care services, given councils access to up to £7.6bn of dedicated funding for social care and will continue to challenge local authorities that do not fulfil their duties under the Care Act".
Only half the councils contacted in England, Scotland, Wales and NI provided data, suggesting the true number of allegations could be far higher.