Mr. Bramhall was subsequently suspended from his position as a consultant surgeon at Birmingham’s Queen Elizabeth hospital in 2013. He resigned a year later, and said his act had been a mistake.
Joyce Robins, who represented Patient Concern, a campaign group, was quoted by The Guardian as saying at the time: “This is a patient we are talking about, not an autograph book.”
At Birmingham Crown Court on Thursday, the lead prosecutor, Tony Badenoch, said that Mr. Bramhall’s guilty pleas “represent an acceptance that that which he did was not just ethically wrong but criminally wrong.”
The surgeon’s actions, he said, were “a highly unusual and complex case” without precedent in criminal law.
“It was an intentional application of unlawful force to a patient whilst anesthetized,” he said. “His acts in marking the livers of those patients were deliberate and conscious acts.”
Prosecutors said they had accepted a plea submitted by Mr. Bramhall denying a more serious charge, assault causing actual bodily harm.
Earlier this year, the General Medical Council issued a formal warning to Mr. Bramhall, saying that while his actions were not serious enough to “require any restriction” on his registration, his conduct had not met the standards required of a doctor.
“It risks bringing the profession into disrepute and it must not be repeated,” the council said.
On Thursday, according to British news reports, Mr. Bramhall was released on unconditional bail, with a sentencing hearing scheduled for January. Assault can be punished with a fine, community service, or in the most serious cases a jail sentence of up to six months.
Mr. Bramhall could not be reached for comment this week.
Tracy Scriven, one of Mr. Bramhall’s former patients, came to his defense.
“Even if he did put his initials on a transplanted liver, is it really that bad?” she told The Birmingham Mail in 2014, after Mr. Bramhall was suspended. “I wouldn’t have cared if he did it to me. The man saved my life.”