His wound was sustained in custody, the Met confirmed. The man, who is in his 40s, has since been returned to the police station. The Met said: “The suspect was taken to a hospital for treatment to a head injury sustained while in custody.
“He has since been discharged and returned to custody.
“We are not prepared to discuss further.”
Met Commissioner Dame Cressida Dick said on Wednesday night that human remains – which have not yet been identified – had been found in an area of woodland in Ashford, in Kent, by detectives investigating Ms Everard’s disappearance.
Scotland Yard said the suspect was treated, discharged and returned to the police station where he is being held.
He was found collapsed and unconscious in his cell on Thursday after suffering serious head wounds, according to the Sun.
The disappearance of the 33-year-old woman has sparked a nationwide debate on women’s safety.
Women across the UK have been speaking out, sharing their fears and frustrations on social media – and there are calls for the law to be strengthened to better protect women.
Labour MP Stella Creasy has made an appeal for the Domestic Abuse Bill to be changed to make misogyny a hate crime.
She said on Twitter: “Today so many women have shared stories of harassment and abuse. Let’s make sure tomorrow this changes – please share this and help win the vote on Monday for Amendment 87B to the Domestic Abuse Bill to make the police properly record misogynistic crimes.”
Sky News journalist Kate McCann also issued a heartfelt plea on Twitter in a thread that has been liked more than 100,000 times.
She said: “What happened to Sarah Everard has hit home hard for so many women because we make the calculations she did every day too.
“We take the longer, better-lit route, push the fear aside for the voice that says ‘don’t be daft, you’ve every right to walk home alone at night and be safe’.”
She added: “You’re a grown woman and in no other area of your life do you feel so vulnerable.
“You resent it even though you understand there is a risk – however small. It is frustrating and tiring and constant. And yet sometimes, despite all those calculations, it still isn’t enough.”
The arrest of a serving police officer has also prompted anger among the Met’s most senior ranks, with Commissioner Dick yesterday voicing frustrations in a televised press conference.
Commenting on the backlash over the police officer’s arrest, chair of the National Police Chiefs’ Council Martin Hewitt said: “Police officers join to keep people safe, so news that a serving police officer has been arrested on suspicion of murder has sent shock, anger and sadness across policing.
“All our thoughts are with Sarah Everard’s family and friends at this terrible time.”
Tributes and messages of support have been flooding in for Ms Everard, with flowers left at the scene near woodland in Kent.
A tribute reads: “From women everywhere, we hope to change the world. All our love x x x x x x.”
Another says: “Sarah Everard we send our love and prayers. We will always remember you.”
A vigil is also being planned on Saturday evening in Clapham Common in south London close to where Ms Everard went missing.