In one of the most turbulent weeks in the financial markets this year, there have been not only tears but also laughter as black humour have helped some of the world’s biggest banks and institutions come to terms with the prospect of huge losses.

As the FTSE 100 shed 4.1 per cent on Thursday – the biggest daily loss in more than four years – traders let rip with expletives and gallows humour in equal proportions as they grappled with the unprecedented volatility.