Caring for an ageing population will strain council services, a councillor has warned, after it was revealed the number of residents aged 85 and over in the borough would rise by 18 per cent in the next eight years.

Linda Kirby made the warning as it was revealed the number of older people in Merton would leap upwards within the next decade - at a time when charities and public spending were massively squeezed.

Merton Council's cabinet member for adult social care and health said: "How are you going to not damage something? You can't."

But Coun Kirby acknowledged residents' care needs would have to be met. She said: "You haven't got any choice - you've got people relying on you."

Lynne Bainbridge, chief executive at charity Age Concern Merton, said the prospect of paying more was already a worry for many. She said: "A lot of older people are anxious about how they're going to pay for care."

Data on Merton's ageing population was published in a council paper entitled Strategic objective review - older people, ahead of a meeting this week. It revealed the number of residents aged 85 and over in the borough was set to rise by 18 per cent, and the total aged 50 to 59 by 24 per cent, by 2019.

The document claimed the council was already hitting care targets and taking a number of steps, from better use of technology to more efficient staffing, to address the issue.

Coun Kirby said the council and voluntary sector would use their "really good relationship" to work together in meeting the demographic challenge. She said good re-ablement services and preventative care would reduce the need for more costly support, and added the council had to resist the temptation to offer care contracts that saved cash at the expense of quality.

"We want to be sure that we are giving the funding to the right people. The specifications have got to be carefully worded," she said.

Her view was backed by Ms Bainbridge, who also said people were less likely to receive care for free in the years ahead. She said: "There will have to be more chargeable services."

Last week the Government-commissioned Dilnot report, an investigation into the future of care in Britain, recommended a new structure for care charges which could cost the treasury £1.7 billion if implemented.