A senior figure at MI5 has said the Security Service could not have prevented Usman Khan’s deadly attack at Fishmongers’ Hall in London, despite knowing that he wrote a play telling of a series of knife murders. Khan killed Jack Merritt and Saskia Jones at a prison education event at the hall in November 2019, within a year of being released on licence for terrorist offences. An anonymous MI5 officer referred to as Witness A told an inquest into their deaths that an intelligence service review of the attack concluded MI5’s actions were “sound”. Witness A said the review found “MI5 could not have taken any action that would have materially changed the outcome on this case”. She confirmed that in early 2019 an MI5 officer read a copy of a play Khan wrote called Drive North that featured a former prisoner who goes on to commit a series of murders with knives. The play, which Khan wrote after attending a creative writing course in prison, concluded with an investigation into whether the deaths could have been prevented, the inquest heard. Giving evidence behind a screen, Witness A said: “At the time we received it in early 2019, they [the MI5 investigation team] saw it as very much part of the literature he had been producing. It didn’t give them cause for concern or add or detract from the united picture – that Khan may re-engage in terrorist activity.” MI5 was made aware that Khan had been invited to a prisoner education event organised by the University of Cambridge’s Learning Together organisation in August 2019 but it was not told it was taking place in Fishmongers’ Hall until 22 November, a week before the attack. Witness A was asked why MI5 did not question Khan’s attendance at the event without a police escort. She repeatedly stated: “At that time there was no intelligence that he should not be allowed to attend.” She also said “preventing people from doing things also has ramifications”. Later Witness A said MI5 saw the event as an opportunity to gain more insight into Khan’s “mindset”. Asked whether the security risk of Khan’s London trip should have been discussed at a joint operation team meeting led by MI5 on 18 November, she said: “Given the awful tragedy it would have been helpful to have had that discussion at the meeting.” Last week the inquest heard that MI5 increased Khan’s threat level from P4 to P3 after he was released from high-security prison in December 2018. On Thursday the inquest at the Guildhall in London was told that P3 refers to individuals “that require further action to determine whether they pose a threat”. Police and probation officers responsible for the management of Khan told the inquest they were not aware MI5 was monitoring Khan or that its officers attended multi-agency public protection arrangements (Mappa) meetings about him in 2019. Witness A confirmed that MI5 was at some of these meetings. “We did attend some Mappa meetings but I’m not able to confirm which meetings we attended,” she said. She said the service was in “receiving mode” during these meetings. She said it was necessary to separate covert investigations from overt management of men such as Khan, to avoid the inadvertent disclosure of information. The witness also revealed that MI5 closed a four-and-a-half-year investigation into Khan in February 2015 while he was in prison for planning to set up a terrorist camp in Pakistan. Explaining the decision, she said: “It was assessed that the residual risk of Khan re-engaging in extremist activity was low.” An investigation was reopened in August 2018 four months before Khan was due for release, the inquest was told. Witness A confirmed MI5 received intelligence that Khan planned to “return to his old ways” after release and aspired to commit a terrorist attack. She said: “We did take steps to validate and corroborate those reports but were unable to do so.” She added: “There was a world of difference between an aspiration and doing the planning that would be required.” The inquest heard that the information of Khan’s terrorist intentions was based on conversations he had with a fellow inmate of Whitemoor prison in Cambridgeshire and was judged to be of “low grade”. Following this intelligence, MI5 increased the priority it placed on Khan from P4 to P3, Witness A said. This would enable some further monitoring and enhance surveillance, she said. This intelligence was shared with counter-terrorism police, Witness A said. But she added it was up to the police whether they shared it with the Staffordshire police Prevent team and the probation service managing Khan. An MI5 review in summer 2019 concluded Khan “could become involved in Tact [Terrorist act] planning,” the inquest heard. Witness A confirmed that in July of that year MI5 objected to Khan being allowed to attend a course to learn how to operate a dumper truck, because of fears he could use a heavy vehicle as a terrorist weapon. Asked why MI5 did not raise similar objections about the Fishmongers’ Hall event, Witness A said: “At that time there was not intelligence that he was engaged in terrorist activity. So there was no intelligence to feed in.” The hearing continues.