Women who falsely report rape have been warned by a judge jail is "inevitable".
Mr Justice Henriques spoke at London's Court of Appeal as Jennifer Day, 35, from Essex, failed to successfully appeal against a two-year prison term.
Day was sentenced in July at Basildon Crown Court after earlier being convicted by a jury of perverting the course of justice.
Mr Justice Henriques said: "Allegations such as this drive yet another nail into the conviction rate."
He called Day's two-year sentence "well-measured" and said scarce police resources were diverted and innocent victims faced a "terrifying allegation".
'Victim's real plight'
"An immediate custodial sentence is inevitable when a false allegation of rape is made," he said.
"Every time a defendant stands trial for rape, defence counsel necessarily point out to the jury that false allegations are made."
Mr Justice Henriques, who was sitting with Mrs Justice Rafferty, read out the words of the Lord Chief Justice, Lord Judge, made in a previous ruling relating to a false rape claim.
Lord Judge had said: "Every false allegation of rape increases the plight of those women who have been victims of this dreadful crime.
"It makes the offence harder to prove and, rightly concerned to avoid the conviction of an innocent man, a jury may find itself unable to be sufficiently sure to return a guilty verdict."