Professor Peter Watson, who represented the Scottish Police Federation (SPF) at the inquiry, said an FAI as “inevitable” and that it could “salvage” the process following the collapse of the public inquiry.

The comments come after the inquiry was plunged into crisis when its chair, Lord Bracadale, resigned amid claims of bias – prompting all five counsel to the inquiry to quit three days later.

Sheku Bayoh, a 31-year-old engineer, died in May 2015 after being restrained by six police officers responding to reports of a man armed with a knife in Kirkcaldy.

Lord Bracadale stepped down last month after it emerged that he had met Mr Bayoh’s family privately on five occasions, raising concerns over impartiality. The meetings came to light only after Chief Constable Jo Farrell reportedly threatened legal action against ministers earlier this year.

Professor Watson said an FAI should now take place to conclude the matter.

He told The Scottish Sun on Sunday: “What we need to salvage from this wreckage is how we go forward to complete the fatal accident inquiry. Somebody is going to have to ask the question: ‘Does this public inquiry continue, can the scope be restricted to a fatal accident inquiry?’ A fatal accident inquiry has to happen.”

The independent public inquiry, set up in 2019, did not begin taking evidence until May 2022 and was tasked with examining whether race played a role in how Mr Bayoh was treated by officers. He had 23 injuries, including a broken rib, and traces of MDMA and the stimulant alpha-PVP in his system when he died in hospital.

Professor Watson said it was wrong to assume a fatal accident inquiry could not consider issues of race. “The myth being perpetuated is that this had to be a public inquiry because it involved race, which could not be dealt with by a fatal accident inquiry. That is not correct. The fatal accident inquiry and the public inquiry walk the same pathway,” he said.

He added that evidence already gathered could be agreed by joint minute, allowing an FAI to be completed in as little as eight weeks. “Eight weeks would be a reasonable-sized FAI because you agree on a lot of evidence by joint minute,” he said.

The public inquiry has cost £26.2 million to date, in addition to £24.3 million spent by Police Scotland. By contrast, Law Society of Scotland data show that the average cost of an FAI was £11,722 in 2015–16 and £6,354 in 2018–19.