Clockwise from top left: Nabeel Kurshid, Mohammed Akhtar, Asif Ali, Salah El-Hakam, Tanweer Hussain Ali, Iqlak Yousaf

The National Crime Agency is reportedly working to trace a total of 426 grooming gangs responsible for abusing an estimated 1,500 victims in Rotherham.

The agency’s investigation into sexual exploitation between 1997 and 2013 has so far resulted in 13 convictions, reported The Independent.

Codenamed Stovewood, the operation could cost £90 million if the government continues its current funding until 2024. The agency is currently running 22 separate investigations under Operation Stovewood and around 290 victims are in touch with officers.

According to the report, the National Crime Agency has so far identified 151 “designated suspects”, and has listed 275 others who it has not been able to name.

A spokesperson for the investigation said 24 suspects have so far been charged and 12 have been arrested and bailed or released under investigation.

Paul Williamson, the senior investigating officer, said the National Crime Agency is “committed to investigate all matters within our remit to bring child sex offenders to justice”.

Earlier this week, seven men were convicted of a total of 24 offences, including rape, sexual assault and false imprisonment, at Sheffield Crown Court.

“I would like to pay tribute to our victims and survivors who have placed their trust in us to support them through this prosecution, and for their courage in giving evidence in what must have been a hugely challenging and emotional experience for them all,” Williamson said, according to The Independent. “This case concerned child sexual exploitation arising from events in Rotherham in the late 1990s and into the next decade.

“The victims and survivors were in their teens when they were targeted and subjected to acts of degrading and violent exploitation and have had to wait a long time for justice which – after a herculean effort over the last three years by my officers – has been delivered.”

The men, all British Asians, were convicted of abusing girls as young as 13 between 1998 and 2005 in Rotherham and the surrounding areas.

The men would ply the girls with alcohol and drugs and pass them around to be sexually assaulted by multiple men. They were threatened with violence if they did not comply with the men’s sexual demands.