A jealous lover who hit his girlfriend 50 times with a hammer in front of their baby daughter had faked an email to make it look like she provoked him, a court has heard.

Asad Niazi killed Charito Cruz, 37, at the home they shared in Cambridge Road, Kingston, having discovered she had rekindled an affair on Facebook with a former lover.

Mr Niazi, 29, admits manslaughter but denies murder on the grounds he was suffering from severe depression at the time of the attack on September 26, 2011.

Prosecutor John Rees told the Old Bailey today that records recovered from the family computer showed Mr Niazi accessed the Filipino nanny’s Yahoo account so he could send a fake message to his own email address.

The message, which taunts Mr Niazi with threats of being sent to jail and not being allowed to see his daughter, was sent to “mitigate the consequences of his intended actions”, he said.

He went on to point to a message posted on the Yahoo Answers forum asking users for advice before he “did something wrong” as further proof he planned to murder Ms Cruz.

Speaking at the hearing today, crown prosecutor Mr Rees described the defendant as “cold and calculating”.

He said: “It is our contention that this sham email was produced by the defendant because he was already contemplating the possibility of killing her and was considering what charges he might face."

Mr Niazi was found cradling the couple’s daughter, then two years old, with the blood of Ms Cruz “splattered all over his face”, after concerned neighbours alerted the landlord, who called police, the court heard.

He is alleged to have told a police officer when he was arrested that “she cheated on me, she deserved it” but later denied making the statement, telling officers he loved Ms Cruz.

He told a child helpline that he was being “pushed to the limits” after discovering Ms Cruz had contacted married ex-boyfriend Michael Gabriel through Facebook, the jury heard.

The pair, who had known each other in the Phillipines, were said to have texted and phoned many times a day, the court was told.

While Ms Cruz was working two jobs in a care home and as a nanny since arriving from the Philippines, Mr Niazi was not allowed to work because of his immigration status from Pakistan.

He refused to cook and clean as he was caring for their daughter, the jury heard.

The day before Ms Cruz's death, Mr Niazi was released on police bail after admitting criminal damage to her iPhone, the court heard.

Ms Cruz made an appointment to visit the domestic violence one-stop-shop in Kingston and made enquiries about changing the locks, the court heard.

The trial is expected to last two weeks.