A 39-year-old man groomed a 13-year-old girl for sex then threatened to petrol bomb her house and put explicit film of on the internet if anyone found out, a jury was told Shabir Ahmed began a sexual relationship with the orthodox Muslim schoolgirl after approaching her in Lister Park, Manningham, Bradford, it is alleged.

Ahmed, then of Windsor Court, Little Horton, Bradford, plied her with vodka and offered her money, Bradford Crown Court heard.

He denies three charges of sexual activity with a child under 16, sexual grooming, two allegations of sexually assaulting her adult sister, attempting to pervert the course of justice and nine charges of possession of indecent photographs of a child.

The court heard Ahmed met the sisters at a fair in Lister Park in the summer of 2010. Prosecutor Caroline Wigin said the young girl, then 12, was more forward than her sister, in her 20s.

She gave Ahmed a mobile phone number and the three met again and went for a ride in his car.

The sisters visited Ahmed at his flat and he offered them alcohol and cigarettes and sexually molested the older sister, Miss Wigin said.

Two weeks later, the sisters went back to the flat when Ahmed ordered the woman to strip naked and was abusive when she refused, it is alleged.

Miss Wigin said a friend of Ahmed began a sexual relationship with the girl, now 13. Her older sister then caught Ahmed having sex with her at his flat, she alleged. Miss Wigin told the jury he said he had recorded the sex and would put it on the internet and he threatened to petrol bomb their house.

The older sister told her aunt and she saw Ahmed through the window having sex with her niece, Miss Wigin said.

The jury heard police seized Ahmed’s laptop computer and found indecent images of girls aged 12 to14.

Ahmed told officers he had no knowledge of the child pornography. He said he used the computer to look at photos of pigeons.

He denied any sexual relationship with the 13-year-old or sexually assaulting her sister.

The trial continues.