Key Asian markets continued to fall sharply overnight with the Nikkei Index in Tokyo down 3.5%, to a new 15-month low - the Australian market is now more than 20% down from its high last April.

Many commentators suggest that the latest severe bout of global selling was triggered by the failure of the Japanese Central Bank’s recent move to stimulate markets by introducing negative interest rates for some overnight bank deposits.

In Europe, The Financial Times reports this morning that Deutsche Bank is considering buying back several billion euros of its senior bond debt in a measure to bolster its capital reserves and to stem the rout on its shares.

The share price of Europe’s largest bank fell another 4% yesterday despite assurances from management and the German finance minister that its finances were rock solid and that it would continue to make interest payments on its junior bond debts.

"No, I have no concerns about Deutsche Bank," finance minister Wolfgang Schauble said, without offering further detail.

Shares in the bank have dropped by almost 40% so far this year.

Other leading continental banks such as Credit Suisse and UniCredit were also down sharply

The publicly-quoted banks in Ireland continue to suffer, Bank of Ireland lost another 2.75% to close below 25c while Permanent TSB has fallen below the €3 and has lost a third of its value since its re-flotation on the stock market last April.

The overall ISEQ index fell more modestly yesterday but has still experienced its worst six-day sell-off since the depths of the recession in 2011.