This case of D is probably one of the most well-known and widely-sighted cases.
In the case of Article 3 medical claims based on physical illness, the threshold was set by D v United Kingdom (1997) 24 EHRR 423.
It meant that the previous threshold test for Article 3 medical claims were unattainably high –
Firstly, there must be exceptional circumstances.
Secondly, it must be shown that the applicant would be exposed to a real risk of dying under most distressing circumstances.
And thirdly, a critical stage must be reached in the applicant’s illness, and the applicant should basically be on their deathbed.
For more information on this test and the D case generally, please read it in full here: https://www.bailii.org/eu/cases/ECHR/1997/25.html