Blackmail

Blackmail was a crime involving threats to reveal information to the public or legal authorities unless paid. Sean Harris tried to blackmail Ed Morgan after he saw him murder Lizzie Lewis using a quantum transducer. Morgan refused and assumed Owen Harper was also after money when he told Morgan he also knew. (TV: Ghost Machine)

Using Lois Habiba's film as leverage, Torchwood Three blackmailed the government to give them access to Thames House. (TV: Children of Earth: Day Four)

Shortly after meeting them, when a broken spring in the fast return switch caused an explosion in the TARDIS, the First Doctor accused Ian Chesterton and Barbara Wright of sabotaging his ship to blackmail him into returning them to 1960s England. (TV: The Edge of Destruction)