The Treasury is to blame for a failure to reform care funding in England, a former Lib Dem minister has said.
Paul Burstow said the Treasury saw no need for change and was happy to "kick the can down the road".
Care groups have backed a proposal that the state cover elderly and disabled people's care costs over £35,000.
The government, which is continuing to look into cheaper options, said the Treasury had played a major part in getting care back onto the agenda.
Ministers have said they support the principle of a cap, proposed by the independent Dilnot Commission - but as yet there is no commitment to finding the money to pay for it.
The Dilnot package would cost the Treasury almost £2bn a year.
The government is expected to include its plans on paying for the cost of care in the next spending review, to begin next year.
Writing in the Daily Telegraph, Mr Burstow - a former care services minister - said there was a "historic opportunity" to change the system for the better but feared that the government would put it "back in the too difficult drawer".
"The coalition made a good start, setting up the Dilnot Commission within two months of taking office. But sustaining that pace has been tough," he said.
One of the reasons behind this was, he said, reluctance from the Treasury to back the reforms.
"The Treasury's view is simple, kick the can down the road despite our rising elderly population. No sense of urgency. No recognition that left unreformed there is no incentive for families to plan and prepare.
"In the view of mandarins there is no need for change, and certainly not yet. That has been the Treasury line every time a reform plan has popped its head above the parapet."
Mr Burstow, who lost his job in the recent reshuffle, said he had received more correspondence from MPs about care costs than any other topic.
"The good news is so far the Treasury has failed to smother the latest plan, a cap on lifetime care costs," he added.
"Ending the scandal of people forced to sell their homes to pay for care would be a legacy for this government felt for generations."
He later told BBC Radio 4's Today programme that the government had made "a lot of progress" on the issue but urged Mr Osborne to show the "political will" to go the final step.
"The division, I think, is between the Treasury and everyone else. Both the prime minister and deputy prime minister have signalled over the summer their determination to see this now happen but that does require the Treasury to actively engage with the Department of Health to work through how you pay for it and actually deliver this reform...
"In the end, it does require the chancellor of the day to actually say 'this has to be a priority and this is now what we are going to deliver'."
A coalition spokesman branded Mr Burstow's remarks as "rubbish".
"Unlike under the previous government, the Treasury has played a major part in getting Dilnot back onto the agenda, not least by working to ensure we have the sustainable public finances that are necessary if it is to be delivered."
Labour said there were "no simple solutions" to the rising cost of caring for the elderly and cross-party co-operation was essential to agree a way forward.
"Labour has been warning for months that the government is kicking long-term care funding into the long grass," Liz Kendall, shadow minister for care and older people, said.
"All the parties must now come together to try and reach consensus about how we tackle the immediate care crisis and develop a better, fairer system for the future."