Leeds "right to die" campaigner Paul Lamb will battle for a change in the law today at the Supreme Court in London.
He will be supported by locked-in syndrome sufferer Tony Nicklinson's widow, and a paralysed road accident victim.
Mr Lamb won the right to join the litigation to continue the case started by Mr Nicklinson before his death last year.
Nine Supreme Court justices will hear the latest round of their fight over the legal ban on voluntary euthanasia.
They want to give people who are physically unable to end their own lives the choice of what they call a ''dignified and humane'' death.