Britain's "neglectful society" will need help from volunteers to cope with the rising number of elderly people, a government minister has said.
Care minister Norman Lamb told the Financial Times modern families and the state were unable to meet demand.
He said the "the dispersal of the extended family" had left many older Britons lonely and said the state could not address the problem "on its own".
He said there was an "overwhelming case" for volunteers to fill the gap.
The Liberal Democrat said the issue of isolation was more urgent than crime in some areas and suggested "a 21st century version of Neighbourhood Watch" to tackle it.
"On our very streets we have people who live on their own, who don't see anyone and whose relatives might visit once a month or whatever, but what's life like in between?" he said.
Mr Lamb compared Britain to Spain, where he said elderly people were looked after by their families, and said Britain had "inadvertently become quite a neglectful society".
He said many families live long distances apart, often because people move to study or for jobs.
Mr Lamb said his call for a greater role for volunteers was not a "cost-cutting option" - but he said the ageing population was "an existential challenge to the system".
He said people who "care about sustaining the NHS" should realise it was necessary to "think more creatively than we've done in the past".
The NHS's budget has been protected from cuts under the coalition government, but it is only rising at the rate of inflation - and population growth and the rising number of older people is increasing pressure on its services.
Office for National Statistics (ONS) figures suggest the proportion of UK people aged 65 and over increased from 15% in 1985 to 17% in 2012 - an increase of 1.7 million people - and is projected to reach 23% by 2035.
According to the Financial Times, a report to be published next week by the Association of Directors of Adult Social Services will say local authorities have made significant cuts in their adult social care budgets since 2010.