Despite the banking crash, the financial sector remains addicted to gambling.

The gambling is done through complex financial contracts known as derivatives, which can last for 10-15 years, and their value depends on uncertain future events.

Financial dealers have no interest in buying/selling copper, gas, electricity, water, oil, wheat or any other commodity, but gamble vast amounts on speculating on their price changes.

This is presented as a risk-management strategy, but creates little social value. If the gambles pay off the speculators collect vast bonuses but if they don't the losses are dumped on to innocent bystanders such as savers and taxpayers.

The UK Government's response, as contained in the Financial Services (Banking Reform) Bill, is to ring-fence the investment/speculative side of banking from the retail side, which primarily focuses on savings and commercial lending. The Government claims that this will protect savers and taxpayers from future banking disasters.

This policy is flawed and on its own will not shield taxpayers and other stakeholders. The reason is that the financial sector will still be permitted to grab ordinary people's savings and use them to gamble in the "financial casinos".

The speculators will be able to shelter behind limited liability and dump their losses on to the rest of society.

Derivatives were central to the collapse of Barings Bank in 1995. Even the winners of the Nobel Prize in Economics who ran Long Term Capital Management (LTCM), a hedge fund, could not continue to pick winners and in 1998 were bailed out by the US Fed.

In 2008, Lehman Brothers collapsed with 1.2 million derivatives contracts that had a face value of nearly $39 trillion (£24.6trn), though the economic exposure was considerably less. Its balance sheet boasted net derivatives assets of $22.2 billion, which turned out to be equivalent to the bookies' receipts. As the financial horses did not reach the winning post, all this became worthless junk and it faced claims from counter parties of $300bn.

Bear Stearns made almost all of its profits from speculative activities. At the time of its collapse in 2008, its derivatives portfolio had a notional or face value of $13.4trn, debts of $384 million and capital of only $11.8bn.

Derivatives have also been central to the demise of Northern Rock, Washington Mutual and the bailout of American International Group (AIG), the world's largest insurer, and the recent demise of MF Global. Last week, Prudential Financial, the second-largest US life insurer, reported a pre-tax loss of $684m from derivatives.

The financial sector has learned nothing from the above. The global annual GDP is $65-70trn but the notional value of the derivatives trade is $1200trn akin to the value of the assets on which gambles are placed.

The annual GDP of UK is around £1.5trn. The entire housing stock of the UK is worth around £4.3trn but Royal Bank of Scotland (RBS), Barclays and HSBC alone have derivatives portfolios with a face value totalling nearly £100trn. The 2011 annual accounts of RBS show that the total notional value of its derivatives is nearly £40trn. It reported assets of £1.5trn against a capital of only £76bn.

The biggest elephant in the room is the assumed asset of derivatives contracts of £530bn, whose actual worth could be considerably less.

The notional value of derivatives held by Barclays is more than £43trn. Its financial statements for the third quarter of 2012 show total assets of £1.6trn and a capital of only £64bn. Of Barclays' assets, £495bn relate to derivatives.

No doubt, Barclays and RBS would claim that their net exposure is less because they may have made counter bets to hedge the risks. But the problem is that these hedges don't always work, as Northern Rock, Bear Stearns, LTCM, AIG, Lehman Brothers and others have found.

The financial sector has to be forced off its addiction to gambling. It should not be permitted to infect the rest of the economy. Therefore, rather than weak ring-fencing, a legally enforced separation of retail and speculative banking is needed.

The directors of speculative banking should be deprived of the benefit of limited liability. This way, the owners of these "financial casinos" would be forced to bear the costs of their own failures.

They should not be able to dump the losses on to the rest of society and their gambling habits would be constrained by the amounts they are prepared to lose.

Speculative banking should also be denied access to publicly funded courts so that taxpayers are not forced to bear the cost of disputes among speculators.

To prevent innocent bystanders from being caught in the negative consequences of speculative activities, legislation should be enacted to ensure that no retail bank, insurance company or pension fund is able to provide any finance to investment banking, without express approval from those directly affected.

Prem Sikka is Professor of Accounting at the University of Essex. This article is based on ideas that Prem Sikka expands further on, in his essay Reforming Banks in Federation Viewpoint (www.ier.org.uk/publications/federation-viewpoint-autumn-2012-no1), published by the Institute of Employment Rights.