A government plan to treat more people in the community has failed to free up hospital beds or save money, a report by the National Audit Office has warned.
The NAO said the Department of Health and NHS England were both over-optimistic about what the Better Care Fund for England could achieve, with planned savings of £511m in the first year of fund never realised.
Although the fund - which was set up with £5.3 billion of NHS and local authority funding in 2015 - has joined up health and social care, it has not led to the expected reduction in hospital workload.
In fact, hospital admissions have increased.
According to the report: "Local areas planned to reduce emergency admissions by 106,000, saving £171 million. However, in 2015/16, the number of emergency admissions increased by 87,000 compared with 2014/15, costing a total of £311 million more than planned."
The number of delayed transfer cases - cases where people are healthy enough to leave hospital, but remain because of a lack of suitable community care - also rose.
Local authorities had estimated that using the fund they would reduce delayed transfers of care cases by 293,000, but instead the number increased by 185,000, "costing a total of £146 million more than planned", the report said.
The NHS is suffering from to record-high numbers of delayed transfer cases, while councils, which arrange and pay for some of the care, are also under pressure due to budget cuts.
The report also found that nearly £2 billion set aside to help integrate services had actually been used to plug deficits at NHS trusts.
Amyas Morse, head of the NAO, said: "So far, benefits have fallen far short of plans, despite much effort. It will be important to learn from the over-optimism of such plans when implementing the much larger NHS sustainability and transformation plans."
An NHS England spokeswoman said: "The obvious lesson for the next phase of care integration is that joining up local NHS and council services may be worthwhile, but is not by itself a silver bullet solution to wider pressures on health and social care."
A Department of Health spokesman said the fund was "just one element of this government's programme to integrate health and social care".
He noted that the report also attributed some benefits to the fund, including that it had "incentivised local areas to work together better, with nine out of ten places saying their plans are improving services for patients".
The NAO report found that 90% of local areas agreed or strongly agreed that delivery of their plan had improved joint working.