Some campaigners want the law on assisted suicide changed
A woman suffering from multiple sclerosis is appealing to the House of Lords for clarification over the law on assisted suicide.
Debbie Purdy, aged 46 from Bradford, wants a guarantee her husband will not face prosecution if he helps her go to the Swiss clinic Dignitas.
What is the court case about?
Ms Purdy, who was diagnosed with MS in 1995, has suggested that in the future she may want to travel abroad to the Swiss Dignitas clinic to die.
She wants her husband by her side but wants clarification on whether he will be prosecuted on his return home.
The judicial review was granted on the grounds that the Director of Public Prosecutions (DPP) had acted illegally by not providing guidance on how decisions over prosecutions are made.
Her legal team argued the right to respect for her private and personal life, enshrined in Article 8 of the European Convention on Human Rights, was being breached because of lack of clarity in the law.
What did the High Court decide?
Last year two senior judges said current guidelines were adequate and did not require clarification.
They also said her human rights had not been breached.
Lord Justice Scott Baker said: "We cannot leave this case without expressing great sympathy for Ms Purdy, her husband and others in a similar position who wish to know in advance whether they will face prosecution for doing what many would regard as something that the law should permit, namely to help a loved one go abroad to end their suffering when they are unable to do it on their own.
"This would involve a change in the law. The offence of assisted suicide is very widely drawn to cover all manner of different circumstances; only Parliament can change it."
This stance was supported by the Appeal Court earlier this year, leaving the Law Lords as the last opportunity for her to get the guarantee in the UK legal system.
She could however take the case to Europe.
What does the current law say?
The 1961 Suicide Act makes it an offence to aid, abet, counsel or procure a suicide or a suicide attempt in England and Wales.
The law is almost identical in Northern Ireland.
Suicide is not illegal in Scotland but the law on assisted suicide is not clear and there is continuing uncertainty.
To date more than 100 UK citizens have travelled to the Swiss Dignitas clinic to end their life.
Although cases have been investigated by the DPP, no relative has been prosecuted.
Ms Purdy has argued it is not clear how those decisions are reached or what exactly is classed as aiding or abetting assisted suicide.
Lawyers for the DPP said the law does not require a specific policy and that the provisions of the 1961 Suicide Act provide sufficient information.
Has anyone else tried to challenge the law?
In 2001, Diane Pretty, who had motor neurone disease, failed in her bid to get immunity from prosecution for her husband if he helped her to die in the UK.
There have also been several attempts to legalise assisted suicide in Britain but these have been rejected.
The most recent, in 2006, was defeated in the House of Lords by 148 votes to 100.