A 16-year-old boy has been arrested on suspicion of terrorism offences after officers discovered an “unknown substance” during a routine raid, Scotland Yard said. The teenager was detained on suspicion of the “commission, preparation or instigation” of offences under the Terrorism Act after police searched a property in west London on Wednesday morning.

Local officers carried out the raid at about 9.55am and found an imitation firearm and cannabis plants as well as the unknown substance, Metropolitan police said. The latter find prompted an escalation to the counterterrorism command and the substance will be sent for urgent analysis to determine what it is, the force said.

The boy was also arrested on suspicion of possessing an imitation firearm and the cultivation of cannabis and is being held at a south London police station while inquiries continue.(theguardian)…[+]