Clarence Mitchell reports: The government is insisting that no deal was done to end the strike

Horne, aged 46, called off his hunger strike on Sunday. He had been demanding that the Labour government honour a pre-election pledge to announce the setting up of a royal commission to look into animal experiments.

Horne's supporters, the Animals Betrayed Coalition (ABC), said he ended his protest after he "accepted the latest government proposals of an independent analysis of vivisection".

The ABC said Horne had been reviewing documents from the government and had decided that they had sufficient positive contents to call off the strike.

However some have cast doubt on the seriousness of Horne's protest.

Barbara Davies, deputy director of the Research Defence Society, told BBC News Online: "As far as we can see it's a publicity stunt."

The RDS's director, Dr Mark Matfield, was one of the scientists whom another animal rights group, the Animal Rights Militia, had threatened to kill if Horne died.

'No clinical need'

Ms Davies also questioned whether Horne had actually been on hunger strike, given that he was sent back to prison last week after doctors decided that he had no irreversible damage, while his supporters had said that he had been given the last rites three weeks before and that he had been losing his sight and his liver was failing.

Horne, who is serving 18 years for firebombing, was sent back to Full Sutton prison on Thursday after doctors at York District Hospital said there was "no clinical need" for him to remain in an outside hospital, taking account of his refusal of food and medical treatment.

But a statement on Horne's support Website from 10 December says that his doctor told his next-of-kin shortly before he was moved back to prison: "Barry could die tonight or at any time in the future."

The doctor also said: "His damaged eyesight, due to paralysis of nerves in the brain, could be irreversible."

And in an update on Horne's health on 2 December, a statement on the site reads: "Doctors today stated that the damage Barry's body has suffered is irreversible."

'Outrageous' claims

Questions have also been raised as to whether the animal rights campaigner took any food during his strike.

Claims such as these are rejected by the Animals Betrayed Coalition. Spokesperson Clare Ellis told BBC News Online: "He didn't take any food.

"While studying the government documents he did drink orange juice and sweet tea," she said, and there had never been any secrecy about this.

Responding to critics who say that the hunger strike had been a sham, Ms Ellis said: "Ask them to try going 68 days without food - it's outrageous."

Ms Ellis said Horne had achieved a great deal through his protest in "revealing to more people what's going on in the laboratories".

She added that the government had now put animal welfare higher on its agenda and was now aware of the strength of feeling surrounding the debate.

"People do want action and we will go around campaigning to make sure they get it," Ms Ellis pledged.

But she admitted that Horne had not achieved his primary goal of getting the government to set a date for a royal commission.

'No negotiation'

The government had maintained a "consistent" position throughout the hunger strike, the Home Office said.

"The government never ruled out nor announced a royal commission," a spokesperson told BBC News Online. There had been "no negotiation at all" with Horne during his protest.

Ms Davies said: "The government has not given into his blackmail. The only thing Horne has done is to raise the issue in the public sphere ... and we welcome the debate."

Horne is said to have decided to call off his protest after Michael Banner, chairman of the government's advisory committee on animal experiments, the Animal Procedures Committee, said he welcomed an invitation to meet the all-parliamentary group on animal welfare.

Ms Ellis said: "The APC spent 45 minuutes discussing Barry last week."