The Princess Royal Trust for Carers has urged the three main political parties to provide explicit guarantees about supporting carers in their election manifestos.
The charity made the call as it warned of an "unacceptable" silence from the government and the Conservatives and Liberal Democrats about how they would support carers should they form the next government.
It called for four guarantees: an assurance that the government's national carers strategy will not be abandoned; a carers' centre is provided in every area; a recognition that every carer has the right to breaks, and higher benefits to help carers avoid poverty.
The charity, which provides support services for carers, has said it is concerned that the next elected government could fail "millions of unpaid carers" without whom support for older and disabled people could not be delivered.
The trust's chief executive, Carole Cochrane, said: "We are deeply concerned that the next elected government could fail millions of unpaid carers. It is unacceptable that the three main parties have not made any clear indications about supporting carers or even if carers will be included in their manifestos."
There are currently six million people in the UK looking after a family member who is sick, disabled or has a mental health or substance misuse problem. They save the government an estimated £87bn a year.
Recently the government announced measures to help carers into employment, including providing funding for replacement care while they go on training courses.
However, a long-promised review of carers' benefits is yet to be carried out. The Department for Work and Pensions has not set out a timetable for doing so, despite widespread concern that current provision is inadequate.
The carers strategy, published in June 2008. pledged that no carer would be left in financial hardship and allocated £150m to primary care trusts to fund short breaks from 2008-10. However, a survey by the trust last year found that 80% of the £50m allocated in 2008-9 had not been spent on its desired purpose.
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