A Crown Court judge has been criticised for treating a rape by a teenager as a "childish prank gone wrong".
The youth raped a girl while his friend held her down. They were sentenced at Sheffield Crown Court earlier in 2006.
After admitting rape, the youth, now 17, received a 24-month detention order and his accomplice received an 18-month order for aiding and abetting rape.
The Appeal Court increased the rapist's term to four years and his friend, also 17, received three-and-a-half years.
The Appeal Court judges agreed with submissions made on behalf of the Solicitor-General, Mike O'Brien, that their terms were "unduly lenient".
"The sentencing judge seems to have approached this case as a childish prank gone wrong," said Mrs Justice Hallett, sitting with Mr Justice Silber and Mr Justice Tugendhat. "It was not", she added.
The two teenagers and the victim had gone to the house of another youth in Grimsby late last year and played computer games in his bedroom, the court was told.
The girl said she repeatedly protested when the first student made advances towards her, but he eventually pushed her on the bed and got on top of her while the other two youths were in the room.
She said she tried to get up, but he pulled her jeans down, and told his friend: "Grab her hands and I will give you a fiver".
Mrs Justice Hallett said the youth then did so, meaning the girl was unable to defend herself.
The victim said she kept asking them to stop, but the youth holding her hands said: "I can't, I am being paid".
"She felt the offence of rape had ruined her life," Mrs Justice Hallett said.
"Had the judge had the benefit of a victim impact statement, he might have appreciated that the offence was more serious than he seems to have thought."
Mrs Justice Hallett said that in Judge Bullimore's sentencing remarks he spoke of the effect on the offenders and their families, but made no reference to the lasting consequences on the victim or her family.
"That was, in our judgment, unfortunate to say the least," she said.
"Whether or not the victim impact statement was available to him, it should have been glaringly obvious that a 16-year-old girl raped in those circumstances was going to suffer long-term and grave consequences.
Both offenders were said to be immature and naive, and both came from loving and supportive families.
Mrs Justice Hallett said the case was not a childish prank gone wrong, but the calculated rape of a young girl, in the presence of three young men, despite her protests.
"In our view, this was a very serious offence and one - whatever their ages - which merited a substantial period of detention."
She said the Appeal Court could not understand Judge Bullimore's observations that "in some circumstances" he might have imposed a non-custodial sentence on the youth who held down her hands.
Nor did they understand why Judge Bullimore said he could "understand" why that youth had not pleaded guilty - a situation, Mrs Justice Hallett said, which forced the victim to relive her ordeal in the witness box.