Mr Haldane, who advised Mr Burnham before he returned to Westminster, claimed the markets believed he is presiding over a “traditional tax and spend socialist government”.

The president of the British Chambers of Commerce said investors and markets have retreated into worrying over the UK’s public debt load.

He told LBC: “The fiscal Achilles’ heel of this government thus far has been its unwillingness and/or inability to cut public spending. Within financial markets, we’ve gone from the cautious optimism of the summer months to the studied scepticism of September.”

“The market now suspects that this is a traditional tax-and-spend socialist government with better TikTok videos.” Mr Haldane renewed his calls to consider replacing the triple lock pension. The uprating mechanism on the state pension is expected to cost the government up to £40bn more a year by 2050, according to the Institute for Fiscal Studies.

He added: “Truth be told, when the triple lock came in, pensioner poverty was sky-high, and it’s done its work. That’s been beaten back to a relatively low level. If not now, when?”

The top economist urged the government to focus on other spending areas, such as the NHS, arguing that improving productivity across the public sector would give Mr Burnham and Chancellor John Healey “instant credibility”.