The Government's Victims' Champion Sara Payne said she was "sickened" by Soham murderer Ian Huntley's six-figure claim for compensation after he was badly injured by another inmate.
The killer of schoolgirls Holly Wells and Jessica Chapman had his throat slashed in March and now says the prison service failed in their duty of care towards him.
It was reported he could recoup almost £100,000, though the Ministry of Justice said the claim would be "vigorously defended".
Ms Payne, who received £8,000 in compensation when her eight-year-old daughter Sarah was abducted and murdered by convicted sex offender Roy Whiting 10 years ago, said Huntley "shouldn't get a penny".
"I got £8,000. Can anyone honestly tell me it can be right that the killer of Holly and Jessica should get £100,000? He shouldn't get a penny. It is appalling to think he could have that as a nest egg if he is ever freed," she told the Sunday Express. "But sadly I believe that the compensation culture of modern Britain will give him everything he is asking for and maybe even more. It sickens me."
Campaigner Norman Brennan, the founder of the Victims of Crime Trust, said Huntley should drop his claim and be "thankful" he was not hanged. He said: "If Huntley had the slightest remorse for the terrible murder of these two girls he would drop the case immediately and get on with serving his sentence, and just be thankful it's not pre-1967 when he may well have been sentenced to the hangman's noose."
Mr Brennan, 51 and now retired from the police, said inmates convicted of such heinous crimes should forfeit their right to sue.
He said if Huntley won his claim, the families should sue him for every penny. "What message is sent out when the two families in this matter received a maximum £11,000 and yet Huntley, for injuries received while serving a sentence, could get many times that. Huntley is the one responsible for being in prison. He should shut up."
The former school caretaker, who murdered the 10-year-old friends in Cambridgeshire in 2002 and is serving a life sentence, was left scarred by the attack at Frankland Prison, County Durham.
He is alleged to have been cut with a razor blade by Damien Fowkes and needed hospital treatment. He was attacked previously and has attempted to kill himself several times.