Whistleblowers have exposed some of the world’s biggest scandals in corporate history. They have unmasked fraud, sexual misconduct, corruption, tax evasion and other misdeeds at great personal risk. But daring to speak up and hold organisations to account comes at a price.

As UK regulators prepare an overhaul of their existing whistleblowing programmes, according to people familiar with the matter, Financial News spoke to five of the most high-profile whistleblowers in the world about their experiences.