The former HSBC currency trader at the heart of a US fraud investigation spent more than two years on a panel that advised the Bank of England, it has emerged, as the Department of Justice widens its probe to examine more currency trades.

Stuart Scott, who left HSBC in late 2014, has “strongly denied” allegations that he ramped up the price of the pound ahead of a $3.5bn (£2.7bn) currency deal for the oil firm Cairn. A warrant was out for the British trader’s arrest yesterday after his former colleague Mark Johnson, HSBC’s global head of foreign exchange, was freed on $1m bail in New York.

Mr Scott last night remained tight-lipped about his possible extradiction, leaving his house only briefly to hand over a piece of paper with details of his solicitors.

The Cairn trade took place in December 2011, months after Mr Scott joined the Bank of England’s chief dealers’ subgroup, which was set up to inform officials about the mechanics of the market in quarterly meetings.