It is beyond ironic that an investment strategy that claimed to eliminate risk threatened the unprecedented failure of the UK pension system this week.

The main focus of attention so far in probing what went wrong has been on what took place over the few days leading up to the Bank of England’s emergency intervention on Wednesday to stem a crisis in pension funds over so-called liability driven investment strategies.

These strategies aim to hedge the liabilities of funds to meet their pension promises with the use of derivatives. But they suddenly exposed the sector to a now infamous “doom loop”, when falls in gilt prices triggered calls on schemes to provide more collateral on such trades, in turn spurring more sales of UK government bonds to raise cash.