Former inmates of a detention centre who claim they were sexually or physically abused have asked the home secretary, Sajid Javid, for their own public inquiry.

John McCabe, a former inmate of Medomsley detention centre, recently told Javid in a private meeting at the House of Commons that the victims he represented had been failed by the ongoing independent inquiry into child sexual abuse (IICSA).

Because the cut-off point for victims is 18 at the public inquiry, evidence will not be heard from those who were aged between 18 and 21 when they say they were abused, even though the age of homosexual consent was 21 at the time.

In November 2017 seven former members of staff, aged between 61 and 74, were charged with abuse and misconduct.

The inquiry recently concluded a two-week investigation into the abuse of children in custodial institutions but McCabe is frustrated at the exclusion of older victims. Meanwhile, the investigation into Medomsley has been delayed by legal proceedings.

The inquiry, established to examine how the country’s institutions handled their duty of care to protect children from sexual abuse, has been marred in controversy since it was announced in 2014 by the then home secretary Theresa May. In 2016, Dame Lowell Goddard became the third chair to resign, saying the inquiry’s remit was too complex, too broad and went back too far (60 years).

McCabe told the home secretary that the victims of Medomsley will have been denied justice if they were not granted their own public inquiry at the end of the criminal prosecutions. “According to the terms of the IICSA inquiry, they were not children at the time they were abused. Yet we were sent to Medomsley rather than prison because we were young and vulnerable. For the victims who have been excluded from giving evidence, it is like being abused all over again.”

McCabe said IICSA was an inappropriate forum for detention centre victims to be heard because it was only examining sexual abuse. “This means that those people who suffered physical abuse will not get the opportunity to give evidence,” he said.

“The victims were in the care of the state when they were abused. The state failed in its duty of care then. I asked the home secretary to exercise that duty of care now by ordering a separate public inquiry.”

Laura Pidcock, the MP for North West Durham and shadow minister for Labour, attended the meeting with McCabe and Javid. “It is important that the current criminal proceedings continue unimpeded,” she said. “But it is also right that a separate, thorough-going, public inquiry is granted for Medomsley once these criminal processes are concluded.”

A spokesperson for the Home Office said: “IICSA is independent of government and it is for the chair and panel to determine the scope of its investigations within its terms of reference.”