Two men convicted of raping young girls have had their "unduly lenient" two-year prison sentences doubled by the Court of Appeal.
Simon Foster (L) and Keith Fenn were both jailed in June this year
Devon chef Simon Foster, 26, raped a 12-year-old girl, and Oxford window cleaner Keith Fenn, 25, raped a 10-year-old girl.
Attorney General Baroness Scotland argued in court their original terms should not be allowed to stand.
Both men had their two-year sentences doubled from two to four years.
Fenn, of Blackbird Leys, Oxford, had been due to be released on 19 October after taking into account his time spent in prison waiting for his sentence.
He was jailed at Oxford Crown Court in June this year by Judge Julian Hall after he pleaded guilty to two charges of rape against a 10-year-old.
Foster, of Britannia Avenue, Dartmouth, Devon, was also sentenced the same month at Exeter Crown Court by Judge Jeffery Rucker after he admitted a series of sexual offences against a 12-year-old girl, including two counts of rape.
In both cases, lawyers said the men thought the girls were older and they did not have to force them to have sex.
Baroness Scotland urged appeal judges to increase the jail terms
Neither Fenn or Foster were present for the ruling by Lord Justice Latham, Mr Justice Stanley Burnton and Mr Justice Pitchford on Friday.
Baroness Scotland, the government's most senior law officer, said in a statement that she welcomed the judgement.
She said: "I am grateful for their Lordships' careful consideration of the case.
"Keith Fenn and Simon Foster's victims were young and vulnerable girls, there was a considerable disparity in age between the offenders and victims and the sentences fell substantially short of the sentencing guidelines issued by the independent Sentencing Guidelines Council.
"Sentences in cases such as this need to punish offenders for the harm they cause, protect children and act as a deterrent to others."
The appeal judges had been told that the girls in both cases, who cannot be identified for legal reasons, were physically mature and developed and both appeared older than their years.
Fenn's victim had told him she was 16, while the girl Foster raped had said she was 15 years old.
Baroness Scotland told the judges her concern was that in both cases "too great a discount has been afforded to the offenders by the judges who sentenced them, for the ostensible consent of the victim and the offenders' belief as to the victim's age".
"The message must be that sexual activity with girls of 10 and 12 will not be tolerated," she said.
Darren Horsman, from the Judicial Communications Office, said there is no criticism by the Court of Appeal of the judges' rulings.
The appeal judges have instead "clarified" the law relating to defendants who claim that they thought the victim was over the age of consent.
He said that gives judges a precedent for future cases.
Det Insp Simon Snell from Devon and Cornwall Police welcomed the judgement.
He said: " We believe that this sentence reflects the seriousness of the crime committed".