Councils will struggle to cope with the financial challenge posed by England's ageing population, a watchdog says.

The Audit Commission said the £9bn a year social care bill will double by 2026 if current practices continue.

The warning comes as ministers are considering a revamp of the funding system for social care.

But the Commission said councils needed to look at new and innovative ways to provide services, particularly by embracing technology.

It highlighted a number of examples of how "telecare" was being used to provide electronic links between services and people living in their own homes.

The variation between local authorities is unacceptable   Stephen Burke, Counsel and Care

It cited examples where councils had fitted exit sensors, fall detectors and flood alerts - in case people left taps running - to monitor vulnerable people in their own homes.

The watchdog also said an increased involvement of neighbours was another solution to the growing demands.

And it raised concerns about the variation in spending levels on services such as meals, care at home, assessment systems and nursing support. In some areas, these cost three times more than in others.

Highest needs

Audit Commission chairman Michael O'Higgins said: "There are huge financial pressures on councils in the years ahead, but redesigning services and exploiting technology can make them better, more efficient and more personal."

Stephen Burke, chief executive of the Counsel and Care charity, added: "The variation between local authorities is unacceptable."

But David Rogers, of the Local Government Association, said local authorities were well aware of the issues.

"We are acutely aware that the future will mean doing things differently to cope with an ageing population, developing new technology with less funding from the public purse and are already making huge strides to adapt to the future."

The report comes as the government prepares to publish detailed plans in the coming months into how social care should be funded.

The current system is means-tested, but campaigners and the political parties all agree the arrangements are unfair, as more and more people are being excluded from services by greater restrictions on eligibility which are being imposed by councils.

Labour has pledged to introduce free personal care so people with the "highest needs" can stay at home.

The party has put forward several proposals, including a compulsory levy on people's estates which the Conservatives have dubbed a "death tax".