Last month I attended a political briefing organised by the Chartered Accountants of Scotland. Held in the run-up to the General Election, it was a chance to hear the major UK political parties’ perspectives on the economic challenges facing Britain over the next five years.

The discussion was notable for what was not discussed: quantitative easing (QE). Perhaps the only mention of the subject was when I asked this question: “how do the political parties anticipate the unwinding of QE in the next parliament, and how worried are you about the implications of the whole process on economic activity in general and the financial markets in particular?”

So, why did I ask this question? And should we be worried?

In 2009, the then Chancellor of the Exchequer shot the starting pistol on what is arguably the most radical and unconventional monetary experiment in the UK’s history. As interest rates had already been cut to 0.5 percent, leaving little room for manoeuvre, he authorised the Bank of England to set up an Asset Purchase Facility to buy high-quality assets, such as Government bonds and commercial paper, to inject liquidity into the credit markets. This extra demand, they hoped, would stop sell-offs and convince investors that the Government was in control of the situation.

In 2009, the then Chancellor of the Exchequer shot the starting pistol on what is arguably the most radical and unconventional monetary experiment in the UK’s history.

The total amount purchased was a very, very significant £375bn between 2009 and 2013.

Today, all political parties are agreed it was needed and appropriate. Many doubters argued it would cause hyper-inflation, but inflation in the UK is now zero percent; others argued there would be a run on the markets, but the FTSE and Nasdaq are now at all-time highs. But what is less clear is how QE will be unwound and what the consequences of unwinding will be.

The reserves of central banks in the UK, USA and now the Eurozone have ballooned. As we return to normality, central banks will have to deleverage sooner or later. The problem is that these mass purchases propped up asset prices and occasioned vast shifts in portfolio allocations in search of yield, typically taking investors down the credit quality curve.

This means that when central banks choose — or are forced — to deleverage, we should expect asset prices to fall. Worryingly, as these prices fall, the very value of the central banks’ holdings would take a significant hit. Even a small fall in asset prices would cause huge losses for central banks and their shareholders, their respective governments. This threatens to undermine their credibility as a mass sell-off is triggered.

Worryingly, as these prices fall, the very value of the central banks’ holdings would take a significant hit.

Greater market turbulence would appear to be in prospect.

We have already seen what might happen in the so-called ‘tamper tantrums’ in the US — and the run on emerging markets more recently. In June 2013, when ex-Fed Chair Ben Bernanke laid out the conditions under which the bank would begin thinking about reducing the pace of asset purchases, US equity and bond prices tumbled. He hastily reworded his guidance to rolling over the maturing debts and keeping the Fed’s balance sheet at the same high level.

This would be made worse — or, should I say, even worse — If global central banks decided to all deleverage at the same time.

As the election approaches, we now need to start asking some serious — and humbling — questions about unwinding QE. Too much time has been spent discussing fiscal policy, which, while important, is much less pressing. It is time the political parties said quite clearly how they are going to manage this deleveraging process.