Multiple sclerosis sufferer Debbie Purdy must wait to learn whether she has won her legal battle to clarify the law on assisted suicide.

Today, the second day of the hearing at London's High Court, Lord Justice Scott Baker and Mr Justice Aikens reserved judgment on a case with important implications for many who are terminally ill.

Wheelchair-bound Ms Purdy, of Undercliffe, intends, if life becomes unbearable because of her illness, to travel abroad to a clinic in Switzerland or Belgium where people can end their lives by lethal injection.

But assisting suicide in the UK is unlawful and punishable by up to 14 years' imprisonment, and she fears that her husband, Cuban jazz violinist Omar Puente, 46, could face prosecution if he helps her.

Her lawyers are seeking a High Court declaration that the Director of Public Prosecutions, Sir Ken Macdonald, is obliged under human rights laws to spell out in clearer terms the circumstances and the factors which might lead to a prosecution.

But today Dinah Rose QC, appearing for the DPP, argued the courts could offer her "no comfort".

Ms Purdy, whose legal action is being supported by Dignity in Dying, formerly the Voluntary Euthanasia Society, has accused the DPP of "cowardice" for refusing to give further guidance on what she regards as an "inhumane" law.

Critics say any change in the law to make assisted suicide easier could put the vulnerable and disabled at risk of exploitation and abuse.

The judges gave pro-life group the Society for the Protection of Unborn Children (SPUC) permission to intervene and put a written statement of its views before the court.

No one has yet been prosecuted for helping a loved one fly abroad to die.

But Ms Purdy, 45, said yesterday: "As long as the DPP will not clarify his policy, I worry that as my husband is black and a foreigner, this makes him a more likely target for prosecution."

Her lawyers argued in court that she was entitled to know whether her husband would be at risk if he bought plane tickets, accompanied her abroad, or carried out other acts to help her die with dignity.

Today Dinah Rose QC, appearing for the DPP, said: "With respect, Ms Purdy cannot achieve by these proceedings the comfort she says she seeks.

"No one can give her that reassurance that her husband will not be prosecuted because assisting suicide is a criminal offence."

The only way to achieve that comfort was by persuading Parliament to amend the Suicide Act 1961, which makes it an offence to aid, abet, counsel or procure a suicide or a suicide attempt.

Ms Rose rejected accusations that Ms Purdy's 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.

The provisions of the Suicide Act itself, when coupled with guidance in the Code for Crown Prosecutors, provided enough information to comply with the convention, she argued.

The law currently provided sufficient flexibility to judge each individual case on its merits in a situation where there could be no "advance immunity", and the DPP was not obliged to create a specific policy.

Ms Purdy, a music journalist before her illness, lived an adventurous life including trekking through jungles and jumping out of planes before being diagnosed with primary progressive MS in 1995.

The court heard she has been in a wheelchair since 2001, and her ability to carry out everyday tasks is deteriorating.

She said before the hearing: "My dearest wish would be to die with dignity in my own home, with my husband and other loved ones around me."

But she is a member of Dignitas, the Swiss organisation which operates clinics for assisted suicide, and believes there could come a time when she would wish to end her life and have to travel abroad.

Her husband is willing to risk prison to help her, but Ms Purdy said: "For 13 years I've been in love with this man, he's everything to me, and I`m not about to see him take a risk of prosecution."

David Pannick QC, appearing for Ms Purdy, warned that a failure to win her legal battle could unnecessarily shorten her life.

He said: "Her dilemma is that she wants to delay her suicide as long as possible.

"If her husband is likely to be prosecuted, then she is much more likely to travel abroad to commit suicide sooner rather than later."