Dennis Cockburn was the Metropolitan Police Service Detective Chief Superintendent during the 1960s and 1970s. He was implicated in the MPS corruption scandal of 1970, despite being reluctant to follow Commander Harold Chapple in drinking on the job and accepting bribes, and having served on the force for 24 years. Ultimately, Commissioner Colin Blamire fired him and promoted John Salway in his stead, as he was upset that Cockburn had backed the outsider Roy Johnson in becoming the head of the inquiry into the MPS' corruption. He then became Chapple's assistant, being demoted.