A mother has confessed to killing her two children in a Spanish hotel room, court officials said yesterday.

Lianne Smith, 43, was held by police in Lloret de Mar on the Costa Brava after Rebecca, five, and her 11-month-old brother Daniel were found dead on Tuesday. According to reports, they had been suffocated.

The children died on the same day that Ms Smith's partner Martin Smith, 45, was extradited to Britain to face child sex charges.

One of Britain's most wanted men until his arrest by Spanish police earlier this month, Mr Smith allegedly jumped bail in 2008 while facing charges of rape of a child under 16, gross indecency with a girl under 16, indecent assault of a girl under 16 and attempted rape of a girl under 16.

A spokesman for Staffordshire Police said they originally attempted to trace his partner and her daughter after they left their home in the area in 2007.

"As soon as we became aware of the arrest of Martin Smith we instigated a welfare check - through authorities in Spain - on Lianne and Rebecca." he said.

"We were informed that they were safe and well. Lianne declined all offers of police help and support and stated her intention to remain in Spain - as was her legal right - and not to return to the UK. At this point we also became aware of the existence of Rebecca's younger brother."

Ms Smith had been a manager in Cumbria County Council's children's services department before the family moved to Staffordshire in October 2007.

It has been reported that Ms Smith, who is believed to have run a nursery in Barcelona, was worried the Spanish authorities would take her children away and that she planned to kill herself, leaving her children with a minder.

But in the end she could not bear to be parted from the youngsters.

The children's nanny said she believed Ms Smith intended to leave the two infants in her care and go off and kill herself.

Spanish police are investigating the death of the children, reported to have been suffocated with a plastic bag.

It was suggested in the Spanish press yesterday they died on Monday night rather than Tuesday.

Their mother would have then spent that night in her room in the Hotel Miramar with their bodies, local newspaper El Punt reported.

Post-mortem examinations were carried out yesterday but the results have not been made public as the judge overseeing the investigation has ruled they should be conducted in secret.

They are believed to have confirmed that the children died from suffocation.

In a statement, court officials said: "Smith spontaneously declared that she had killed her two children."

Martin Smith, originally from North Shields, who is the father of the children, appeared before Carlisle magistrates on Wednesday charged with 13 sexual offences and one for jumping bail.

A statement issued by the court following the hearing read: "Forensic psychologists carried out an examination for the arrested woman, Ms Smith, concluding that she was conscious and aware of the situation and that the results of the psychological tests were normal ...

"A statement was taken from Ms Smith in the presence of a lawyer, a translator and the public prosecutor. She was read her rights."

She was seen being led into prison in Girona yesterday afternoon looking tired and drawn.