The NHS is 'wasting precious time and money' on outsourcing services, trade union Unison is claiming.
A report for the union by the Office for Public Management is highly critical of aspects of the commissioning process.
The researchers, who interviewed NHS managers, were told by commissioners that they had concerns about "marketisation", complex tendering processes, and inconsistency across the country.
One said: "[Commissioning decisions up to this point] have just been to do with what are we going to commission our NHS trust to do. We have not been out there stimulating the market or blazing a trail."
Another said: "We are used to just going along to the local trust and talking to them and saying 'can we just change this a bit?'.
"It is the NHS family. You can't go along to [a private provider] and say the same - they will say no."
Providers said they faced difficulty managing to be both flexible and follow the terms of a contract.
Checks and balances
Unison general secretary Dave Prentis said: "It is a slippery slope when health reforms are brought in without the necessary checks and balances of effective scrutiny and accountability.
"At a time when finances are increasingly tight, the NHS cannot afford to be throwing precious money away to the private sector and wasting time and resources on the complexity of the commissioning process."