The case Debbie Purdy was decided upon by the highest British court on 30 July 2009. The lawsuit lasted for two years. Apart from the actual verdict, the law lords' decision includes first and foremost a command towards the prosecuting body which is of importance for the future: the law lords command the prosecuting body to enact binding guidelines, from which it can be seen if and when a prosecution has to be expected in cases of assisted suicide. In a first reaction to this decision, Keir Starmer, the head of the British prosecuting body, expressed his consent with the verdict. Corresponding guidelines have been issued in February 2010. These guidelines declare criteria like the difference between "encouraging" and "assisting" suicide, the ability of the deceased to commit suicide themselves, age, whether there was an express wish to suicide, the relationship between the deceased and the assisting person and if the assisting person profits from the deceased's death as significant for the decision on prosecution. The decision for or against prosecution after an assisted and/or encouraged suicide is clearly laid out to be a case-to-case decision, which takes the public interest into consideration.

Since their (then provisional) publication in September 2009, the guidelines have served as a basis for judicial procedures. The case Cari Loder became the first criminal investigation to which the guidelines have been applied on 11 January, 2010. Loder took her own life in June 2009 after a severe neurological disease. Criminal investigations have been conducted against a member of the pro-euthanasia group "Friends at the End", Dr. Libby Wilson, who stood in telephone contact with Ms Loder only a few days prior to Ms Loder's suicide. In accordance with Starmer's guidelines, the case did not come to prosecution.