Care for the elderly is in crisis and the system will be unable to cope with increasing demands of an ageing population, campaigners warn.

The Caring Choices coalition - a group of campaign organisations - has warned that one in five people in the UK will develop long-term care needs, and claims the current method of providing for the elderly is not sustainable.

The charities say there is not enough cash being invested in the service and not enough is being directed towards preventative care.

The King's Fund, Help the Aged, Age Concern and the Joseph Rowntree Foundation are leading a group of 15 organisations which are hosting debates around the UK to highlight what they see as failings and to challenge government and providers to search for solutions.

The debates will focus on funding, how much people should pay towards care and how much families should be expected to bear.

The campaign will centre on evidence from Sir Derek Wanless's review of social care funding for older people for the King's Fund.

Even though Scotland has a free personal care policy, concerns remain about future funding being sufficient to cope with growing numbers and a perceived lack of standardisation of implementation across the country.

The charities fear few people are aware what they will have to pay for when they are older.

They fear with an ageing population the problem will worsen and people will have to pay more costs themselves.

Mervyn Kohler, of Help the Aged, said: "Many people get a nasty surprise when they develop care needs and discover that they may have to pick up the bill. Getting the balance between what is fair for individuals to contribute and what the state should pay is the first step towards creating fairer system all round."

Gordon Lishman, director-general of Age Concern, said: "As our population ages, more and more people will be confronted with this uncomfortable truth, and you can see the anxiety already. Now is the time to discuss honestly and openly about making the system work for all."

A Scottish debate takes place in Edinburgh on Wednesday July 4.

Meanwhile, the Registered Nursing Home Association has warned of problems of social isolation for older people following government statistics showing a rise in the number of people living alone.

It is predicted that one-third of people in the 223,000 one-person households to be created across the UK by 2026 will be over 65.

Frank Ursell of the RNHA said: "Too many of our senior citizens feel abandoned, not just in terms of their physical and emotional isolation but in terms of having to pay for the care which throughout their lives they had presumed would be provided for them by the system they paid into."

Julia Unwin, director of the Joseph Rowntree Foundation, said: "We need a plan B for social care funding. The current system is neither fair, clear or sustainable and the time has come to devise a system that is fit for the 21st century."