The Attorney General will appeal against the sentence given to a window cleaner for raping a 10-year-old girl on the grounds it was unduly lenient.
The Attorney General will appeal against the sentence
Keith Fenn, 24, will be free in five weeks after a judge said the girl, who was assaulted in Henley-on-Thames, Oxfordshire, had appeared older.
Judge Julian Hall told a select committee of MPs that he stood by the sentence he handed to Fenn.
A spokesman for the Attorney General confirmed the move on Friday.
He said: "The Attorney General, Baroness Scotland has decided to refer the sentence of Keith Fenn to the Court of Appeal.
"After careful consideration of the evidence, advice from counsel, and taking into account the age and vulnerability of the victim, she has concluded the sentence imposed was unduly lenient.
"She does not believe the sentence sends a clear enough message that the rape of a 10-year-old under any circumstances is a grave offence, and must be dealt with seriously by the courts.
"It will now be for the Court of Appeal to decide at a future hearing whether or not to increase the sentence."
During the trial in June, Oxford Crown Court heard that Fenn, from Blackbird Leys in Oxford, raped the girl in a park on 14 October 2006, before an accomplice, Darren Wright, 34, took her home and sexually assaulted her.
Judge Hall said in sentencing he faced a moral dilemma as the fact they had sex within 45 minutes of meeting was an absolute crime.
But he said the girl had dressed provocatively and looked as though she was 16.
Lawyers for the defendants stressed that the sex had been consensual, and was only termed rape because of the framework of law.
The judge gave Fenn concurrent two-year and 18-month sentences, but he will be free in five weeks after serving eight months in prison awaiting sentence.
Judge Hall later appeared before the House of Commons constitutional affairs select committee to give evidence for their inquiry into "effective sentencing".
When asked about the sentencing, he said he stood by his decision and did not want to add anything to what he had said in court.