Lianne Smith (45) told a court she had used plastic shopping bag to suffocate 5-year-old Rebecca and 11-month-old Daniel to death in May 2010.
The Girona provincial court in north-east Spain was stunned to hear Smith recounting her macabre killings in a recorded interview with the police. She said as Daniel struggled for breath, she drew the bag closed around his neck and 'did not stop squeezing' until he was dead,
The Daily Mail reported. Then she did the same to her daughter before giving her children a cuddle and spending the night beside their bodies.
Smith claimed she killed her children because she feared they would be taken from her by social services after her partner TV psychic Martin Smith to whom she wasn't married was arrested on child sex charges.
The couple fled to Spain in December 2007 but in May 2010 Martin Smith was tracked down and deported to face trial in the UK. The prosecution on June 17 called for her to be jailed for 38 years, while the defence wanted her to be acquitted on mental health grounds. The trial continues.