Central and local government are unaware how long adult social care systems can cope under mounting pressure, a report has suggested.

Government departments do not know how close the adult care system is to reaching capacity, while major health reforms set to be introduced by the Care Bill will cause further ‘significant challenges’ for councils – according to the National Audit Office (NAO).

Town hall spending on adult social care fell by 8% between 2010/11 and 2012/13, with 87% of adults now living in regions that arrange services only for individuals with substantial or critical needs.

While the Department for Communities and Local Government expects service transformation, local efficiency initiatives and the Better Care Fund will ease financial pressures, the NAO said there was ‘weak evidence’ for which way of commissioning services was most effective.

Auditors added that efforts by DCLG and the Department of Health to understand the impact of changes or reduced spending on care, welfare and local services were not being matched by other government departments.

A Government spokesperson said: ‘We are creating a £3.8bn Better Care Fund to join up NHS and social care services. This will help to keep people living independently at home, get them out of hospital more quickly and prevent them from needing more support. We are giving councils £1.1bn funding to help protect social care services in 2014/15.’

‘Councils have proven that by joining up services, people still get the care they need and they save money,’ the spokesperson added. ‘Councils across the country need be more innovative so they can meet the needs of their communities.’

Head of the NAO, Amyas Morse, said: ‘There are no easy answers, but we need to think clearly and in a joined-up way about the predictable and growing challenges in years to come.’

Chair of the Committee of Public Accounts, Margaret Hodge, said: ‘The DoH and the DCLG are changing the adult social care provision when it has no idea whether the changes will actually deliver savings. The result is unnecessary stress and an unfair financial burden on those who need care and the 5.4 million unofficial carers.’