Pretty was diagnosed with motor neurone disease several years before. Over time, the disease worsened and made it impossible for her to move or communicate easily even though her mental faculties remained normal. The illness resulted in her having to be looked after round the clock by her husband and nurses, meaning that she could not take her own life, which she had said she would do if she was able to. She stated a wish that her husband should be able to assist her in ending her life, but this would be classed as assisted suicide, which is illegal in the United Kingdom. Pretty took her case to court using the Human Rights Act to argue that the Director of Public Prosecutions should make a commitment not to prosecute anybody involved in helping her to die. British courts did not accept Pretty's arguments, with the House of Lords, Britain's highest court, eventually turning her case down. The European Court of Human Rights refused to acknowledge that the European Convention on Human Rights provided a right to die, and her appeal to that court also failed.
Diane Pretty died aged 43 on May 11 2002 as in the preceding months her health had deteriorated rapidly due to a series of lung and chest problems.