A senior U.K. policeman says that British undercover officers often used the identities of dead children as aliases, confirming a recent newspaper report which first exposed the ghoulish practice.

Chief Constable Mick Creedon said Friday that the tactic was once "common practice" at London's Metropolitan Police, also known as Scotland Yard.

Stealing the identities of dead people is a classic piece of spycraft and features prominently in Frederick Forsythe's famed 1971 thriller "The Day of the Jackal."

But the Guardian newspaper's revelation that British police were using the tactic to spy on protesters disturbed activists, lawmakers, and law enforcement officials alike.

Creedon, who has been leading the inquiry into police undercover tactics since February, is also investigating reports that undercover officers fathered children with their surveillance targets.