Olaseni Lewis, a 23-year-old British man, died on 3 September 2010 at Bethlem Royal Hospital in London, United Kingdom, after police subjected him to prolonged physical restraint.

South London and Maudsley NHS Foundation Trust, the body managing Bethlem, received no charges, though it made changes to its internal processes as a result.

Lewis's death returned to national attention in 2020 following the George Floyd protests in the United Kingdom, in relation to the disproportionate number of black, Asian and minority ethnic people killed by UK law enforcement officers.

He attended Kingston University in south London and, regarded as a bright student, went on to study a master's degree in business and information technology there.

[5] Following the UK summer bank holiday weekend, Lewis suffered an acute psychotic illness over a period of 48 hours in late August 2010.

Lewis's state caused accident and emergency doctors there to ask his family to agree that he be taken to a place of safety, under section 136 of the Mental Health Act 1983.

[8][9] Ajibola Lewis reflected that a nurse at Maudsley advised her not to send her son there, saying "as a young black man in London, it's very easy to be picked on" and a doctor suggested she treat the issue as a "one-off".

Lewis voluntarily admitted himself to the hospital on the basis that he could leave if he desired and that his family would be contacted in the event of any problem.

[14] Lewis died the same day as Colin Holt, another black man with mental health issues who was restrained by police.

[15] In 2011, Lewis's family attended an annual march on Downing Street to protest the deaths of Black Britons in police custody.

The families of others who died in police custody, including Jimmy Mubenga, Kingsley Burrell, Jacob Michael, Smiley Culture and Mark Duggan, attended the march.

[18] The death of Lewis, among others, contributed to the creation of a Commons Select Committee review of Policing and Mental Health in 2015.

[19] An initial inquiry in 2011 by the Independent Police Complaints Commission (IPCC) first cleared officers over the death and noted that no disciplinary measures were required.

[20] After a new inquiry opened into the death of Sean Rigg, another Black British man with mental health issues who died in police custody, the IPCC announced it would also review its original investigation of the Lewis case.

The High Court ruled in the families favour in September 2013[20] Following the conclusion of a second IPCC inquiry and a review by a Queen's Counsel in early 2013, the Crown Prosecution Service (CPS) noted that there was insufficient evidence to bring a conviction against the officers who restrained Lewis.

Raju Bhatt, the solicitor for the Lewis family, said he was not surprised by this outcome but would continued to push for full investigation of the incident in the face of "four-and-a-half years of prevarication and worse".

[22] In May 2016 a senior coroner raised concerns about the standard of statements provided by staff at Bethlem, as their impartiality would be affected by the fact that their legal representation was being paid for by their employer, South London and Maudsley NHS Foundation Trust, which was involved in the case for corporate manslaughter.

[6] The inquiry remarked on the fact that ABD is a police definition with no medical basis and that officers may be better served by general guidance on risks when restraining mentally ill people.

[6] At coroner's inquest the jury found many failures by both police and medical staff which played a part in Lewis's death.

The jury found that "The police failed to follow their training, which requires them to place an unresponsive person into the recovery position and if necessary administer life support.

Eleven police officers were involved in holding down a terrified young man until his complete collapse, legs and hands bound in limb restraints, while mental health staff stood by.

Lewis's death was highlighted as an example of the disproportionate number of black, Asian and minority ethnic people killed in police custody.