A 14-year-old accused of the double murder of two Tooting sisters has admitted searching “how to burn someone's house” on the internet hours before the home of the girl he had just split up with was torched.

But, giving evidence at the Old Bailey this afternoon, the boy denied murder and said he “loved” Maleha Masud.

Maleha, 15, and her sister Nabiha, 21, died after the arson attack on their Lessingham Avenue home about 4.30am on Sunday, June 21, last year.

The boy, from Croydon, and two men, Rasal Khan, 19, from Leicester, and Shihabuddin Choudhury, 21, of Nottingham, deny two counts of murder and three counts of attempted murder.

The teenager said he would often speak to his fellow defendant Mr Choudhury about the relationship with Maleha and that the pair split two days before the attack because he was “jealous” about her talking to other boys and also because of an argument about him going abroad.

He said: “On the Saturday morning I had a conversation with [Mr Choudhury} . . . I didn't know what to do I was frustrated and annoyed.”

He said he spoke to Choudhury on the phone or the MSN website and only searched the internet after he was asked to. The teenager told the court: “He [Choudhury] told me to type in how to burn someone's house down. He told me to type in these words. Then me being me I typed it in without asking him why didn't he do it himself, I just typed in what he told me.”

He said Mr Choudhury knew where the Masud house was as they had driven past it before.

The teenager added he and Maleha had been seeing each other since March 2009 but kept their relationship a secret from their Muslim parents. “I loved her, I cared about her,” he said, admitting he was “really annoyed,” when they split and told Maleha's mum of their relationship.

After fire spread through the house, the youngest Masud son, Junaid, 18, was found by firefighters in his bedroom after suffering burns and serious smoke inhalation damage. He spent 45 days in intensive care following the attack.

Maleha, who shared a room with Junaid, died four days after the arson attack from burns and smoke inhalation. Nabiha, a South Thames College student, who was engaged to be married, was resuscitated by paramedics at the scene but died a month after her sister from organ failure, brought-on by inhaling smoke.

Their brother Zain, 24, and the family’s mother Rubina, 55, both escaped the fire by jumping out of a first floor window.

Earlier the court was told the three defendants set fire to the home in revenge for the pair splitting and that the teenager saved a photo of the burnt out house after the arson as the screensaver on his computer.

The case continues.