Skip to main content

The Manchester Arena Inquiry has now concluded. The closure notice from the Inquiry Chairman is available here.

Volume Three: Radicalisation and Preventability
Volume Three: Radicalisation and Preventability (20pt version)

Part 23 Planning and preparation for the Attack

Key findings

  • The device created by SA and HA was designed to kill and injure as many people as possible.
  • SA and HA are likely to have developed their ability to construct their device from viewing an Islamic State instructional video that was at one stage available online, and also from training they received in Libya in 2016.
  • SA and HA took extensive steps to avoid detection in the period prior to their departure for Libya on 15th April 2017 and SA continued those steps following his return to the UK on 18th May 2017.
  • The police investigation into the Attack, Operation Manteline, was effective, impressive and professional.
  • HA confessed his involvement in the Attack to members of the Inquiry Legal Team. In that confession, he revealed that he and SA were motivated by adherence to Islamic State.
  • The evidence, while creating reasonable suspicions regarding other individuals, is insufficient to establish on the balance of probabilities that any of those who participated in the acquisition of precursor chemicals knew that those chemicals were to be used in a bomb. However, there were people in Libya who probably knew what SA intended to do.


The device created by SA and HA was devastatingly destructive. It was intended to be so. In the words of the expert in explosives who assisted the criminal investigation, Lorna Philp: “[T]he design and construction of this device was a deliberate attempt to cause a large explosion that would injure and kill as many people as possible.1 It took approximately six months for the device to be assembled. It required components from a number of sources. It also required considerable knowledge.

As I explained in Part 1 in Volume 1 of my Report, between 15th April 2017 and 18th May 2017, SA was in Libya.2 On his return, he conducted hostile reconnaissance of the Arena on a number of occasions. I will set out that hostile reconnaissance in greater detail in paragraphs 23.91 to 23.93, 23.110 to 23.114, and 23.120.

Following the Attack, the criminal investigation was led by Detective Chief Superintendent (DCS) Simon Barraclough as Senior Investigating Officer. This investigation was conducted under the operational name ‘Operation Manteline’.3 I have heard evidence from a number of officers involved in Operation Manteline, including DCS Barraclough. I have also had the benefit of the support of Operation Manteline officers, who have carried out investigations on my behalf during the Inquiry.

Operation Manteline was an impressive, effective and professional investigation. It resulted in the conviction of HA on 22 counts of murder and other offences. I am grateful to DCS Barraclough and his team for the assistance they gave me. That assistance provided the evidential basis for what follows in this Part.

Following a ruling made by Mr Justice Jeremy Baker in the trial of HA, it has been necessary to assign ciphers to the names of four witnesses, Trial Witness 1, Trial Witness 2, Trial Witness 3 and Trial Witness 4, and withhold their addresses and relationship with SA and HA. As a result, it has also been necessary to assign ciphers to three of these witnesses’ relatives, Relative A, Relative B and Relative C.

In this Part, I set out the steps that SA and HA went through from their first acquisition of precursor chemicals through to the final stage carried out by SA alone. I deal with the period following SA’s return from Libya on a day‑by‑day basis. At the end of this Part, I consider some relevant events after the Attack. I conclude by considering the question of the extent of the involvement of others.