Former White House chief strategist Steve Bannon is to speak to investigators as part of ex-FBI chief Robert Mueller’s probe into Russian election interference, sources have revealed.

Mr Bannon is expected to be interviewed by prosecutors instead of testifying before a US grand jury. He is also expected to co-operate with special counsel Mr Mueller, according to an insider.

It is unclear when the interview will occur.

Mr Bannon, the former head of Breitbart News, appeared before the US House Intelligence Committee on Tuesday, but refused to answer questions about his time on Donald Trump’s presidential transition team and in the White House.

He left the White House in August and has since had a messy falling out with the president.