When the UK’s financial regulator slapped a £26m fine on Barclays for lax controls related to the gold fix, it offered more ammunition to critics of the near-century-old benchmark. But it also gave precious metal traders in the City of London plenty to think about.

While the Financial Conduct Authority says the case appears to be a one off – the work of a single trader – some market professionals have a different view. They claim the practice of nudging a tradeable benchmark in order to protect a “digital” derivatives contract – as a Barclays employee did – was routine in the industry.

One former precious metals manager at a big investment bank says there has long been an understanding among market participants that sellers and buyers of digitals would try to protect their positions if the benchmark price and barrier were close together near expiry.

“These are not Ma and Pa products, they are for super-professionals,” says the former manager. “There’s a fundamental belief that both parties can aggress or defend their book, and I would have expected my traders to do so.”

The gold trader familiar with the Barclays case expresses some sympathy for Mr Plunkett, saying in the pre-financial crisis days the trader may have been censured by his bosses if he had not defended the digital option sold by the bank.

“What’s changed now is the market morality,” he says.