Sara Payne was made Victims' Champion at the beginning of this year
Child protection campaigner Sara Payne's condition has improved after she was taken to hospital with complications following brain surgery.
Ms Payne, 40, fell ill on Wednesday and was taken to St George's Hospital in Tooting, south London, in a critical condition but is now said to be stable.
Friends said she underwent surgery in 2008 to cure a ruptured aneurysm.
Her eight-year-old daughter Sarah was kidnapped from a field in West Sussex in 2000 and murdered by Roy Whiting.
Ms Payne, of Surrey, was appointed an MBE for services to child protection in the 2008 New Year Honours List.
A family source said: "The early signs of her treatment were positive."
Director of campaign group Kidscape Michele Elliott, who is also a friend, said: "Sara is the most wonderful and indomitable person and if anyone can get through this, it's her.
"Everyone needs to pray and send their good thoughts at this difficult time. I have been in tears."
Justice Secretary Jack Straw said: "Our thoughts are with Sara and her family."
Ms Elliott said relatives and friends had been at her hospital.
A spokesperson said on Thursday: "We can confirm that Sara Payne is receiving care at St George's and is currently in a stable condition."
Serial sex offender
Ms Payne began working to protect children from paedophiles and speaking out for victims after her daughter was murdered.
It emerged during the case that Whiting was a serial sex offender who had also abducted and sexually assaulted a nine-year-old girl five years before he killed Sarah Payne.
After Whiting was convicted and jailed for life she called on the government to change the law surrounding information about paedophiles.
The so-called "Sarah's Law" was partly inspired by Megan's Law in the United States, which was introduced after the rape and murder of seven-year-old Megan Kanka in 1994.
Ms Payne was made Victims' Champion at the beginning of this year, a 12-month post in which she was tasked with providing an independent public voice for victims of and witnesses to crime.