On August 5, 2016, the pro-ISIS Cyber Kahilafah Telegram channel posted a message that read "Hacking SCADA. Soon Soon."
SCADA (Supervisory Control and Data Acquisition) systems are used for remote monitoring and control and are often used to control and manage utility and transportation infrastructure. The Cyber Kahilafah post included an image taken from the movie London Has Fallen, showing a London power-grid SCADA-type system being hacked by malicious code. This could indicate the desired target of the attack.
Source: Cyber Kahilafah Telegram Channel, August 5, 2016.