Overview
- Aimen Dean, a former Al-Qaeda member who later worked undercover for MI5 and MI6, said another 9/11- or 7/7-scale attack is a matter of when, not if.
- Dean claimed there are hundreds of sleeper agents in the UK and argued Iran poses the greatest danger to Britain and Europe, with more lone actors likely.
- The UK terrorism threat level remains at substantial, which means an attack is considered likely under the government’s scale.
- MI5 assesses Islamist terrorism as the most significant threat by volume, while ministers report a 48% rise in state threat investigations over the past year.
- Officials say Britain has disrupted 20 potentially lethal Iranian-backed plots since 2022, with the October 2 Manchester synagogue attack cited as recent context.