Over-75s are being left lonely and isolated particularly in London, a think-tank has warned, and more resources should be used for their care rather than younger pensioners.
The Institute for Public Policy Research (IPPR) and the City of London Corporation's City Bridge Trust published a report that quoted recent research suggesting nearly a fifth (18%) of over-75s "felt lonely much of the time during the past week", compared to 11.8% of 65 to 74-year-olds.
While a quarter (25.6%) of 65 to 74-year-olds live alone, nearly half (44.5%) of over-75s do so.
Clare Thomas, chief grants officer at the City Bridge Trust, said: "We asked IPPR to help us further our understanding of the complex and diverse needs of London's fast increasing older population and to help us target our resources most efficiently.
"With the number of older people in London set to rise dramatically, this report highlights the urgent need to tackle social isolation amongst the oldest members of our society.
"By targeting services specifically at those aged over 75, rather than those simply over retirement age, policymakers can reach those most at need and ensure they do not slip through the gaps in service provision. Loneliness must no longer be seen as an acceptable part of old age."
The number of people in London aged over 65 is expected to rise by a third in the next 20 years, and those over 90 by 95%, the report said.
Director of IPPR Nick Pearce said: "Older Londoners are more likely to live alone, suffer from poverty and lack support from their families compared to older people in other areas of the country. The city also faces high rates of population churn, a complex infrastructure and a reliance on migrant workers - which adds to the challenge of designing effective public services. For too many people, growing older is a journey of loss - losing work, mobility and friendships."
The report called for the Greater London Authority to take responsibility for health and social care across the capital, with boroughs sharing information.
It suggested that GPs should give "information prescriptions" to elderly people to make sure that they get the right advice, and that advice workers should be stationed in GP surgeries.