First published on Thu 8 Apr 2021 10.11 EDT One of London’s most senior police officers, described by a colleague as “the greatest villain unhung”, was believed to be involved in major corruption in the 1970s but never prosecuted, according to a new documentary on police malpractice. Former officers who exposed corruption at the time describe how they were threatened that they would end up in a “cement raincoat” if they informed on fellow officers and were shunned by colleagues when they did. The fresh revelations come from half a dozen former officers from both the Metropolitan and City of London police forces, including one who has admitted receiving payments. The claims are made in a three-part documentary series about the widespread acceptance of bribes that led to the setting up of the anti-corruption unit A10, on which Line of Duty’s fictional AC-12 is based.