The family of a 'locked-in' syndrome sufferer who fought for the right to die said Saturday they would continue his campaign to change the law after seeking permission to appeal a High Court ruling.

Tony Nicklinson died on August 22 aged 58 a week after losing a lengthy legal battle to end his life with a doctor's help.

The syndrome left him paralysed from the neck down but fully conscious and aware of his predicament which he had described as "pure torture".

On August 16, High Court judges dismissed Nicklinson's plea for the right to die, ruling it would be wrong to depart from the legal position that "voluntary euthanasia is murder, however understandable the motives may be".

The father-of-two died at the family home in Melksham, western England, after refusing food and contracting pneumonia following the court's decision which he said had left him "devastated".

In a statement issued by his lawyer after the ruling, Nicklinson had said: "I am saddened that the law wants to condemn me to a life of increasing indignity and misery."

Nicklinson had suffered from the syndrome ever since a stroke on a business trip to Athens in 2005.

His family pledged to continue his campaign and have confirmed they have lodged papers with the Court of Appeal asking to allow his widow, Jane, to take up his cause.

Jane Nicklinson vowed in September to press ahead her husband's fight but High Court judges denied her permission to be party to the proceedings in a ruling on October 2.

The judges said they were "deeply conscious of her suffering" since her husband's stroke and of "her frustration and distress over the state of the law" but said they did "not consider that the proposed appeal has any real prospect of success".

The Nicklinson family have confirmed they have lodged papers seeking to overturn that decision.

Jane Nicklinson admitted it was likely to be a long campaign hampered by legal technicalities but said her family was determined to fight for her late husband's cause.

She said: "This is part of Tony's legacy, we're fighting for him, on his behalf.

"We really have no idea of when there will be a decision, and even then it will just give us permission to appeal the High Court ruling.

"But this is a positive step for our campaign. It is a long process, but one we will carry on for as long as we can."

The judges said in their ruling that the law on voluntary euthanasia did not breach human rights and it was for parliament, not the courts, to decide if it should be changed.