Police officers could refuse to answer questions about the death of Sheku Bayoh if their answers could incriminate them, an inquiry has heard.

At a preliminary hearing for the public inquiry into the death of the 31-year-old after being restrained by police, lawyers warned that there could be “unanswered questions and uncertainty” from a lack of answers unless they were given certain immunity.

Lawyers for the Scottish Police Federation and the officers involved want undertakings that no evidence given to the inquiry by any officer will be used against them in any criminal proceedings or used to decide if they should be prosecuted.

Witnesses are more likely to be frank and honest with their inquisitor if there will be no adverse consequences to them arising from their evidence

The argument was supported by the inquiry’s senior counsel, Angela Grahame, who said: “Witnesses are more likely to be frank and honest with their inquisitor if there will be no adverse consequences to them arising from their evidence, such as the use of their evidence in a criminal prosecution or disciplinary proceedings against them.”

The family of Mr Bayoh, through a statement released by lawyer Aamer Anwar, said it would be an “astonishing position” for the officers involved to refuse to give evidence to the inquiry.

Opposing the proposals, Claire Mitchell said: “The family of Sheku Bayoh have a legitimate expectation that police officers will give every assistance after a serious incident.

“And that expectation extends to come into a public inquiry and answering all and any legitimate unreal event questions put to it by the inquiry.”

But in her advice to the inquiry chairman Lord Bracadale, Ms Grahame said that because of witnesses’ right to avoid self-incrimination, the police officers could “refuse to answer questions”.

If that were to happen, Ms Grahame said: “There is a real risk that the inquiry will be perceived to have failed to take all reasonable steps to secure important evidence.

“I am concerned that Mr Bayoh’s relatives and family members, core participants and the general public will be left with unanswered questions and uncertainty and a feeling that they do not have closure on the matter.

“The perception may be one of disappointment and lingering uncertainty.”

Although she acknowledged the objection from Mr Bayoh’s family, she added: “I remain satisfied that it is in the interests of the inquiry and indeed the public interest that the undertakings be sought.”

Ms Grahame also recommended seeking undertakings from the Solicitor General and Deputy Chief Constable of Police Scotland to cover all serving and former police officers for consistency and to avoid potential delays.

Lord Bracadale said he would consider the arguments and announce his decision “as soon as I can”.

Mr Bayoh died in May 2015 after being restrained by officers who were responding to a call in Kirkcaldy, Fife.

The gas engineer’s family claimed race played a part in his death and criticised the subsequent investigation.

An inquiry into his death, announced in December 2019, is considering issues including the circumstances of the death, the post-incident management and the extent to which events leading up to and following Mr Bayoh’s death were affected by his actual or perceived race.

At a previous preliminary hearing last year, Ms Grahame , said there will be no more than six hearings, the last of which will cover race.