Updated

England's top prosecutor unveiled new guidelines that could decriminalize many forms of assisted suicide, saying Wednesday that most people who help close friends or family kill themselves aren't likely to face charges.

Keir Starmer, the director of public prosecutions, warned that there were no guarantees but said those who helped adults end their own lives were unlikely to be prosecuted if they were "wholly motivated by compassion" for someone who is severely disabled or terminally ill.

Starmer was forced to publish detailed guidance for prosecutors after Debbie Purdy, a 46-year-old with multiple sclerosis, sued to force the government to reveal under what circumstances it would press charges against those who help others kill themselves. Purdy said she feared her husband could be prosecuted if he helped her go to the Swiss suicide clinic, and said she needed the guidance so that she could know whether to go abroad before her condition prevented her from traveling by herself.

Purdy's case touched off a national debate about Britain's 1961 assisted suicide law and how it is enforced.

Starmer refused to comment directly on Purdy's case, but said he hoped the interim guidance — a final version is expected next year — would help people considering assisted suicide understand the law.

"The point of the exercise was to give clarity to those who require clarity," Starmer said.

Ludwig A. Minelli, the founder of Dignitas, the Swiss suicide clinic where many Britons have gone to end their lives, said the guidelines seemed to "open the door to the possibility of carrying out assisted suicides in clear cases in England and Wales, without the risk of criminal prosecution."

Starmer's guidance outlined 29 factors that could affect the decision to prosecute. Prosecution would be more likely if a person committing assisted suicide is under 18, or if the person suspected of assisting them is a member of a group that lobbies for assisted suicide. Prosecution would also be more likely if someone helped more than one person kill themself or if the suicide was "pressured or maliciously encouraged."

It said charges would be less likely when the person assisting a suicide was a spouse or partner, as in Purdy's case, or if the person's actions "may be characterized as reluctant assistance in the face of a determined wish on the part of the victim to commit suicide."

Purdy welcomed the guidelines, telling the BBC that, "people will know what they must make sure of before they assist, and hopefully that will give people confidence not to make such a decision until the last possible minute."

But groups opposed to assisted suicide warned that the guidance risked sapping legal protection for the sick and vulnerable.

Dr. Peter Saunders of the group Care Not Killing said that the guidance seemed to make prosecutions less likely in the case where a person committing suicide has severe disabilities or suffers from an incurable degenerative condition.

The classification of severely disabled or terminally ill "covers a very wide range of medical conditions and could arguably include chronic heart disease, Parkinson's, or anyone in a wheelchair," Saunders said. "Is the implication there that people who have these conditions have lives less worth living, or less deserving of protection?"

Church groups also expressed reservations, with the Church of England noting its opposition to assisted suicides — even those motivated by compassion.

Assisted suicide is illegal and carries a maximum 14-year sentence in England and Wales, although prosecutions have been rare. More than 100 Britons have reportedly ended their lives at Swiss suicide clinic Dignitas, but no one in the U.K. has been charged for helping them get there.

In one high-profile case last year, officials ruled that it would not be in the public interest to prosecute the family of 23-year-old partially paralyzed rugby player Daniel James. They helped their son travel to Switzerland, where he committed suicide.

In another recent case, music teacher Guy Button was not prosecuted in his father's suicide — even though he acknowledged sneaking an antique pistol into the hospital so that his father could kill himself in the middle of a busy ward.

Minelli, of Dignitas, said that Starmer's guidance was "sensible for the most part" but argued that there were places where it had not gone far enough.