Central banks across the world have joined together to declare that they stand in “full solidarity” with the Federal Reserve’s chair after the US launched a criminal investigation into Jerome Powell.

The heads of the Bank of England, the European Central Bank and the Bank of Canada are among 11 senior bankers who have signed a statement highlighting the importance of independence in setting interest rates.

“Chair Powell has served with integrity, focused on his mandate and an unwavering commitment to the public interest,” they said.

The Department of Justice is conducting the probe. President Donald Trump has said he did not “know anything” about the investigation.

The investigation comes after a year of relentless attacks on Powell by Trump.

As well as criticising Powell’s decisions on interest rates, Trump has launched personal attacks, calling the Fed chair a “major loser” and a “numbskull”.

Commenting on Powell, the global central bankers said in their joint statement: “To us, he is a respected colleague who is held in the highest regard by all who have worked with him.”