Only one in four unqualified care workers is a trade union member, a survey has shown, leading to concerns over the lack of protection for staff outsourced to the private sector.
Union membership among domiciliary care workers and support workers (24%) is far lower than that of care managers (58%) and qualified social workers (88%), according to the Social Care Workforce Research Unit at King's College London.
Brian Strutton, national secretary of the GMB, said the lack of unionisation in social care had resulted in "appallingly low" pay rates for many workers.
The workforce is among the lowest paid in the economy, with 9% of staff earning less than the minimum wage of £5.93 as of April 2010, according to the Low Pay Commission.
"The fact that union membership is less than 50% affects the bargaining position for social care," said Strutton.
He suggested that union membership was higher among local authority staff, who earn more than their private sector counterparts.
But he said uncertainties over the financial stability of providers such as Southern Cross were driving more private sector care workers towards GMB membership.
Helga Pile, Unison's national officer for social care, said: "Moves towards private sector care delivery and workforce fragmentation have been synonymous with falling union membership, declining standards and a race to the bottom on pay and conditions.
"Some private providers are hostile to union involvement, despite the benefits it can bring to them."
In response, Mike Padgham, chair of the United Kingdom Homecare Association, said responsible providers tried to arrange the best possible terms and conditions for staff. But he admitted that this was becoming more of a challenge: "Providers are being asked to do more for less, and that has a knock-on effect."
There are about 1.75 million care workers in the UK, according to Skills for Care. It is estimated that up to 750,000 are members of a union or professional body, leaving a non-unionised workforce of some one million.
Overall, just under half of the 440 respondents in the Social Care Workforce Research Unit's survey were members of a union or a professional body, with the majority belonging to Unison.
The survey found 88% of social workers were members of a union. However, the College of Social Work estimates that, of the 95,000 social workers in England, roughly 50,000 are not represented by unions or professional bodies.
Dr Shereen Hussein, senior research fellow at the Social Care Workforce Research Unit, explained that the survey represented only a small sample of social workers, rather than the national picture.
But she added: "What these results do confirm is the difference between social workers and social care workers in terms of unionisation."
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