Joan Bakewell said the bidding practice translates into less care
Some councils in Scotland and England are auctioning off homecare contracts to private companies in a bid to drive down the cost of elderly care.
Research conducted for the BBC found that some private companies are delivering care for £12 an hour, £10 less than what it costs local councils.
The so-called 'reverse e-auctions' involve firms bidding against rivals over the internet for the lowest price.
The practice has been condemned by government advisor Dame Joan Bakewell.
To date, four UK councils - including Scotland's capital city, Edinburgh - have run the controversial schemes for care services.
The practice is revealed in Britain's Homecare Scandal: A Panorama Special - an in-depth investigation of care providers in Harrow, York and South Lanarkshire.
Dame Joan, a respected broadcaster and, at 75, the government's special advisor on the elderly, told Panorama: "It is the most uncivilised way to treat old people that I've ever heard.
"The idea of charging down the ladder of costs to force the costs down, down and down and down for the sake of profit is truly immoral - it's scandalous. The lowest bidder is going to cut costs, which means cutting care."
The investigation, which included undercover filming of three homecare providers, found carers rushing between appointments, with some being missed entirely and the reporters heard of an elderly client left to sit in her own excrement.
It found care companies short-changing the elderly who rely on home visits for their basic care.
Andrew Wilson was short-changed on his 30-minute care visits
In the case of Andrew Wilson, 78, South Lanarkshire Council was paying a local private company, Domiciliary Care, to provide four 30-minute visits a day. The investigation found that Mr Wilson was being short-changed by an average of four hours of care every week.
In one example, a 30-minute visit lasted just four minutes. Over the course of a year, that would translate into £2,000 worth of care paid for by the council that the client would not receive.
The homecare industry in the UK is a £1.5bn business that attracts bidders ranging from charities to large healthcare corporations.
In South Lanarkshire the council held an online bidding auction for its homecare contract, with the bids dropping as potential care providers competed to deliver the service for the lowest price.
Domiciliary Care, where the BBC reporter worked undercover and where Mr Wilson is a client, won the contract by bidding £9.95 an hour.
An independent study conducted for the BBC by the London School of Economics found that private companies in England were promising to provide care for an average of £12 an hour, while the cost to the local councils who still deliver the homecare internally averages £22 an hour.
In South Lanarkshire, the council required that the winning bidders demonstrate that they could provide quality care.
Those credentials were provided via a questionnaire on which Domiciliary Care scored 100% - despite having been investigated by regulators.
One of the BBC's undercover reporters felt ill-trained for the job
South Lanarkshire Council declined to be interviewed by the BBC, but did issue a statement saying it is satisfied that the tendering process followed correct procedures.
Domiciliary Care was taken over six months ago by Choices Care Group, which told Panorama that some of the problems uncovered were inherited.
The company said it is deeply sorry to learn of the examples of very poor care practice uncovered by Panorama and added that its own investigation confirmed that some visits were cut short. It said changes are being implemented.
Dame Joan said Britain has to question what kind of society it wants to be when profits take precedence over care.
"Do we want a society which is cutting care for the sake of making profit? I certainly don't and I don't think many people do."
Britain's Homecare Scandal: A Panorama Special, Thursday 9 April 2009 on BBC One at 9 pm.