A senior Metropolitan Police officer accused of failing to report her sister to the authorities to protect her after her sibling sent her a child abuse video had no idea what it was, a court has heard.

Superintendent Novlett Robyn Williams, commended for her work at Notting Hill Carnival and with the victims of the Grenfell Tower disaster, was allegedly trying to save her sister Jennifer Hodge, who lives in Brent.

Williams, 54, is on trial for allegedly failing to tell police of the explicit video, which featured a young girl performing a sex act on a man, sent to her by Hodge via WhatsApp in February last year.

The officer was one of 17 people sent the 54-second video by Hodge, who in turn had received it from her partner, 61-year-old bus driver Dido Massivi.

All three are on trial at the Old Bailey.

Anesta Weekes QC, for Williams, said on Friday that the police officer did not report it because she genuinely did not know what it was and never played the video.

Ms Weekes said the other 16 people had only been able to make out the body of the child from the tile image they could see on the WhatsApp screen.

"All 16 other people played it because they didn't appreciate what had been sent to them," she said.

She added: "My client doesn't play it, she doesn't click on it. An expert found she didn't download the video."

Ms Weekes said that other recipients of the video said they would never have played it if they had known what it was.

One witness said she had originally thought it might be a clip of someone's grandchild.

Andrea Brown, for Hodge, said her client had never been exposed to hardcore porn, and did not really understand what was or was not allowed to be circulated on social media.

Ms Brown compared her client's decision to circulate the footage in order to raise awareness to the shocking images used by anti-abortion activists.

"At protest against abortion - whether you are for or against - you know the people thrusting these images in your face aren't doing it because they are titillated by it.

"They do it because they feel the need to show people the reality of what abortion involves.

"You may think - whether you agree with them or not - that they have a legitimate reason for putting that out there."

She said her client had a "genuinely noble" intention when she circulated the footage.

Lefi Tsiattalou, for Massivi, said he had been trying to "raise the alarm" about the video by sending it to Hodge to send on to Williams.

She said: "Mr Massivi told police, 'I thought Jennifer was going to report it through her sister' - his actions are of a man that wants to ensure that police are aware of these images."

Ms Tsiattalou described Massivi as a "simple man" who was not very computer literate.

Williams said she was at a gym class the morning she received the explicit content and its follow-up message from Hodge pleading for the video to be shared in order to catch the male in the video.

The officer, whose address can only be given as south London, denies possessing an indecent image of a child in February 2018 and corrupt or improper exercise of police powers and privilege.

Massivi, of Brent, , denies two counts of distributing an indecent photograph of a child, and one count of possessing an extreme pornographic image portraying a person having sex with a horse.

Hodge, 56, also of Brent, denies distributing an indecent image of a child.

Jurors are due to commence their deliberations today.