Why is the pound plunging on 30th anniversary of Black Wednesday?

Falls against the dollar are prompted partly by concern about Liz Truss's economic and energy policies

• Pound falls as weak retail sales raise fears UK economy is in recession

The timing could hardly have been more appropriate. On the 30th anniversary of sterling being ejected from Europe's exchange rate mechanism, the pound came under renewed pressure on the currency markets and hit its lowest level against the US dollar in 37 years.

Black Wednesday - 16 September 1992 - has a special place in British postwar economic history: a moment in which the Treasury and the Bank of England took on speculators led by George Soros - and lost.