The Independent Police Complaints Commission will act after the referrals from the Metropolitan Police Authority.

BBC: Phone hacking: IPCC to probe Met press chief Fedorcio

Statistics obtained under the Freedom of Information Act showed the Metropolitan Police has investigated more than 200 crimes involving the weapons in the past three years.

BBC: Stun gun firing

Metropolitan Police detectives held Col Lama under Section 134 of the Criminal Justice Act, a law that defines torture as a "universal jurisdiction" crime.

BBC: Nepal army officer on torture charge granted bail