Scotland�s flagship policy of free personal care for the elderly seems to have fallen victim to its own success. Six years after its introduction, the annual cost of providing it to those living at home has risen by nearly £100m to £224m. Last year alone the bill rose by 21%.

Scotland's flagship policy of free personal care for the elderly seems to have fallen victim to its own success. Six years after its introduction, the annual cost of providing it to those living at home has risen by nearly £100m to £224m. Last year alone the bill rose by 21%. If such trends continue, it is clearly unsustainable.

Yet there is no doubting its popularity. Introduced by the previous Labour-LibDem administration in 2002, the SNP is committed to sustaining it. Today, Scots look askance at undignified squabbles in England over what constitutes publicly-funded nursing care as opposed to privately-funded personal care, with items such as hair-washing subject to demeaning demarcation disputes. And by offering care to all who require it, regardless of means, Scottish councils overcome the traditional reluctance of elderly people to apply for means-tested benefits - witness the low take-up of pensioner credits.

However, from the start free personal care has been dogged by lack of clarity and the failure to anticipate the level of demand. Thousands of elderly people with disabilities had been struggling along without help and off the council radar. By last year, more than 42,000 of them were receiving personal care at home and the bill rose by more than a fifth. Though partly attributable to implementing equal pay provisions and reimbursing charges for meal preparation, much of the jump was occasioned by increased numbers requiring 24-hour and weekend care.

These figures can only continue to rise. Labour-saving new technologies and new drugs to tackle conditions such as Alzheimer's are likely to be more than offset by rising numbers with problems such as obesity and diabetes. Living longer does not necessarily equate to living well. In Scotland the number of over-75s is projected to rise by 80% by 2030. And European Union figures released yesterday predict a tripling in the over-80s to 61 million by 2060. By then there will be just two working people (rather than four) for every retired one.

In April Lord Sutherland, architect of Scotland's free personal care, predicted it will be five years "until the demographics really begin to bite". There are difficult questions to be confronted. Instead of using lower school rolls to shrink class sizes, should we be shifting resources from education to the care of ageing babyboomers?

Should middle-class pensioners with £500,000 homes and copper-bottomed pensions get help ahead of young adults with learning difficulties? Or should income tax or council tax be raised instead? And to what extent should the care of our senior citizens be shouldered by relatives and friends?

These issues are such political hot potatoes that no party seems prepared to handle them.

Instead of being a taboo subject, Scotland's changing demography should be seen as a challenge and an opportunity to explore new models of assisted living, beyond sheltered housing, and new models of working to facilitate those with elderly relatives to care for.

Meanwhile, if the Scottish Government is serious about its commitment to free personal care, it needs to set clearer minimum standards, rather than leaving elderly people to play what amounts to a geographical lottery, and it must ensure that councils have the resources to fund it.