The head of the Financial Services Authority has suggested that it may be time for more unconventional policies to revive Britain's stagnant economy.
Lord Turner said reducing private, business and government debt following the financial crisis could impact economic growth for many years.
It was his final Mansion House speech after four years heading the FSA.
He is seen as one of the leading candidates to take over as the next governor of the Bank of England.
Lord Turner questioned the continuing effectiveness of Bank of England stimulus.
The Bank of England had no choice but to pump money into the economy through its programme of quantitative easing (QE), he said, but questioned whether the policy may be becoming less effective.
"QE alone may be subject to declining marginal impact," he said.
He called for "a willingness to employ still more innovative and unconventional policies".
He did not expand on this, but it is understood he believes the Bank of England should consider telling the Treasury it never has to repay some of the £375bn of government debts the Bank acquired through quantitative easing, BBC business editor Robert Peston says.
As it does not involve injecting money through loans that are expected to be paid back, as quantitative easing is, it is more akin to printing money.
"The economists' slang for this kind of policy is the creation of "helicopter" money, because it is seen as the equivalent of dropping money on all of us from out of a helicopter," Robert Peston says.
Regulators should also be doing more to secure the financial system, according to Lord Turner.
The financial crisis of 2008 was "not a bolt from the blue," he said.
"It arose from poor supervision, from bad rules and structures, from dangerous cultures - and the errors were made by regulators, economists, central bankers and public policy makers, as well as bankers themselves."
He said the amount of capital held by banks as a buffer to protect against any potential crisis was a "small fraction of safe levels".
Lord Turner said much good work had been done to correct these mistakes, but much more needed to be done.
He pointed to new global banking standards, known as Basel lll, which would ensure a far safer banking system, and in the UK to the new regulatory framework to replace the FSA.
He also said "there are increasing signs that many banking industry leaders recognise the need for major change". Some observers have questioned whether the industry has learned lessons from the crisis, arguing that too many bankers have returned to business as usual.
The FSA chief warned of the impact of government spending cuts and households paying down debt, particularly given there was limited room for the central bank to further reduce interest rates, which already stand at a record low of 0.5%.
"If we do not carefully design policy in response, the deflationary impact on economic growth could extend for many years ahead," he said.
The coalition has made reducing the UK's debt levels its main economic priority. To this end, it has implemented a wide range of spending cuts, designed to save money and restore confidence in the UK economy among international investors.
Critics argue that these cuts have simply served to push the UK into a deeper recession - the economy has returned to recession having contracted for the past three quarters.
Away from the UK, Lord Turner said the eurozone must forge closer ties if it is to survive the current debt crisis.
He said banks must be supervised centrally by the European Central Bank, eurozone governments must begin issuing some sort of common debt, often referred to as eurobonds, and move towards common taxation and spending policies.
Some eurozone governments are opposed to some of these measures, not least Germany, which is against any kind of common debt issuance.
He also raised the politically sensitive issue of the eurozone breaking up.
"[The UK] has an enormous national self-interest in the eurozone either taking the steps required to succeed, or, if that is politically unattainable, dissolving in a controlled rather than chaotic fashion."