A report published today revealed that the names of 42 dead children born between 1940 and 1975 had been used by police.
Metropolitan Police chief Bernard Hogan-Howe says he is sorry for the "shock and offense" the tactic caused.
The report indicates that security services may also have used names of the dead.
The report says that families have not been told because that would put undercover agents at risk. Howe indicated at least one family had discovered their child's name had been used.