Police have launched an investigation into a fake Instagram profile which impersonated a campaigner and shared pornographic images of another woman.

Jamie Klingler, co-founder of Reclaim These Streets, was targeted by an unknown person who created a fake Instagram page in her name and posted explicit images of an unknown woman purporting to be her and directing people to a pornographic website, which was also fake.

She reported the incident to the Metropolitan Police, who said at the time that “there was no realistic prospect of identifying any suspects” and so “the crime was closed”.

But the force has told the PA news agency the case has now been reassessed.

A Met spokesman said: “On Tuesday 8 February police received an allegation relating to offensive and indecent images posted on social media.

“An assessment of the available evidence determined that there was no realistic prospect of identifying any suspects and, as such, the crime was closed.

“On Friday 18 February the case was reassessed and an investigation has now been started.

“The complainant has been made aware of the decision.”

After Ms Klingler reported the account to Instagram, it was removed.

London’s Independent Victims’ Commissioner, Claire Waxman, welcomed the Met’s decision to open an investigation.

She said: “I am however concerned that it took complaints via social media, pick up from the press, and enquiries from my office for the police to take this action. If we are going to rebuild trust and confidence in the police, victims must be assured that they will receive a positive response and that their complaints will be thoroughly investigated when they report a crime, and not have their reports quickly dismissed.

“It’s clear from this case, and many others I’ve been made aware of, that the police are still struggling to fully understand and investigate crimes which are committed online, or have an online element.

“Both the police and the CPS need to urgently improve their expertise in this area, as while there are legislative gaps, there are still offences – such as stalking – where they fail to recognise the impact online interactions can have on the victim”.