Independent investigations have been launched into how a former soldier accused of terrorism escaped from HMP Wandsworth, why he was being held in the lower-security prison and whether other high-risk inmates may need to be moved from the jail. The justice secretary, Alex Chalk, told MPs that “no stone must be left unturned” in getting to the bottom of Daniel Khalife’s escape on Wednesday morning and that he was seeking preliminary answers by the end of the week. Among the charges faced by Khalife is that he may have collected, recorded, published or communicated sensitive information that might have been useful to an enemy, in breach of the Official Secrets Act 1911. The country in question is understood to be Iran, although it is unclear how strong the link is alleged to be. Amid questions as to why the 21-year-old was on remand at HMP Wandsworth, a category B rather than a high-security prison, while awaiting trial in relation to alleged terrorism and Official Secrets Act offences, Chalk said he had ordered two independent reviews to assess the risk posed by other prisoners. One will look into the placement and categorisation of all inmates at HMP Wandsworth and the other at all held in the custodial estate charged with terrorism offences. Chalk said investigations would be wide-ranging as Labour called on the government to “get a grip” on the criminal justice system and the Prison Officers’ Association highlighted staffing shortages and budget cuts. “No stone must be left unturned in getting to the bottom of what happened,” he said. “Who was on duty that morning? In what roles, ranging from the kitchen to the prison gate? What protocols were in place? Were they followed?” He said strapping found underneath a vehicle that left HMP Wandsworth at 7.30am on Wednesday appeared to indicate that Khalife may have held on to its underside to escape. The shadow justice secretary, Shabana Mahmood, said his escape “simply beggars belief” and highlighted “catastrophic and multiple failures” in the wider criminal justice system. Rosena Allin-Khan, a Labour MP whose constituency includes HMP Wandsworth, said she raised concerns about staffing levels – as well as conditions – at the prison in December after just seven staff turned up to guard 1,500 inmates on a night shift. Her concerns were echoed by Sir Bob Neill, a Conservative MP who chairs the justice committee, who said problems with staffing at Wandsworth and more widely were “a matter of record”. He added: “There is an issue across the prison service with retaining experienced staff – we have a large number of comparatively inexperienced staff.” Steve Gillan, the general secretary of the Prison Officers’ Association, said: “You cannot take out £900m from the budget with reduced staffing levels up and down the country and expect the Prison Service to operate as if nothing has happened.” The prime minister’s official spokesperson said he still had confidence in Chalk and rejected claims that cuts to the prison service were to blame. “We recognise the need for more staff and that’s why we’ve increased the workforce by 4,000 since 2017,” he said. “We’re hiring 5,000 more across the estate in the coming years. We’re also boosting pay by 7%, so the starting salaries have gone from £22,000 to £30,000. And we’re retaining more staff. The resignation rate amongst junior prison officers is down around 2.5% compared to last year.”