A court in Spain heard disturbing evidence on the second day of a case of British woman Lianne Smith who confessed to killing her two young children while on holiday.

Jurors were shown a shot of a plastic shopping bag from a local supermarket, which Lianne Smith used to suffocate five-year-old Rebecca and her son Daniel, who was only 11 months old.

The children were found dead in a room at the Hotel Miramar, 40 miles north of Barcelona. Smith, 45, tearfully explained how she killed them and cuddled them, in fear that social services were going to take them away.

Her actions came days after her partner, Martin, was found guilty of several child rape charges. Lawyers for Mrs Smith are arguing she was not of sound mind at the time of the killings. Her husband was extradited and jailed in Manchester but was found hanged in his cell earlier this year.

Police officers who arrived on the scene all agreed that Smith, who is seeking an acquittal claiming she was in a state of "psychiatric disturbance", seemed calm when she confessed to the killings the day after carrying them out.

In a video interview with police, Smith demonstrated how she used a plastic shopping bag to suffocate Rebecca and Daniel in their beds in a Costa Brava hotel.

As Daniel struggled for breath, she drew the bag closed around his neck and "did not stop squeezing" until he was dead, Girona provincial court in northeast Spain heard.

Then she did the same to her daughter before giving her children a cuddle and spending the night beside their bodies.

She said she tried to kill herself before telling the hotel receptionist to summon police.

The interview officers recorded in May 2010 in the room next to the one where the killings took place hours earlier was made public for the first time yesterday.

Smith, 45, from Lichfield, Staffordshire, showed no emotion as the jury watched the film.

In it, she is asked what she has done and replies matter-of-factly: "I ended the lives of my two children. Then I lay in the bed beside them. I gave them a cuddle.

"I talked to them until about 9 o'clock then I went into the bathroom." Using her hands, she demonstrated how the shopping bag had covered the mouths and noses of the youngsters.

Smith - a former manager at Cumbria county council's children's services department - described how she had killed Daniel first, saying: "I put a bag on his head. All of the head was in. [I knew when he was dead] because I was holding him."

Asked if her daughter had put up a struggle, Smith replied simply: 'She moved, yes.'

The defendant spent the night in the hotel room with her dead children, writing a series of notes.

One to Rebecca and Daniel said: "I love you very much. I wanted to give you a lovely life together. I'm very sorry."

The case continues.