In August 2006, British police disrupted a suspected Islamist plot to detonate improvised liquid explosives on transatlantic flights departing Heathrow Airport. Investigators said the attackers intended to disguise the materials as soft drinks and, if carried out, the operation could have caused mass casualties and fundamentally altered aviation security.

The investigation led to the arrest of 24 people and relied on surveillance, intercepted communications and evidence recovered in raids. The plot was linked to flights bound for the United States and Canada, and its discovery prompted the continuing restrictions on carrying liquids larger than 100ml in cabin baggage.