Three Court of Appeal judges ruled that the terms being served by Rogel McMorris, 18, and Jason Brew, 19, were "unduly lenient" because the case was so "horrifying".

The victim, who has learning difficulties, was disfigured for life in the gang rape in Tottenham, north London, last year.

The men were jailed at London's Wood Green Crown Court on January 19.

McMorris, of Tottenham, north London, who was convicted of two rape counts and one of causing grievous bodily harm, will serve 14 years instead of nine.

Brew, of Haringey, north London, who was found guilty of one charge of rape, had his six-year sentence raised to nine years.

The judges decided not to increase the sentence imposed on Hector Muaimba, 21, of Waltham Forest, east London, who was also found guilty of one charge of rape.

He was sentenced to six years for the attack and is serving an additional two years for a separate conviction for robbery.

The cases of the three men were referred to the Court of Appeal by Attorney General Baroness Scotland, to determine whether they should have been given harsher sentences.

During the hearing, the victim - who has a mental age of eight - was described as having suffered "appalling injuries" in the attack.

Lord Judge said she had "catastrophic burns to about 50% of her body" and had been "marked and maimed for the rest of her life".

"She must have suffered the most horrendous pain, and quite apart from the pain she suffered her life will have been affected for ever," he added.

Learning disability charity Mencap welcomed the tougher sentences.

David Congdon, the charity's head of campaigns and policy, said: "The short sentencing for such a brutal act of violence against a teenager with a learning disability was inexplicable.

"All too often victims of abuse who have a learning disability are treated as second class citizens.

"Crimes against people with a learning disability must be taken seriously and treated exactly the same as those against people without a disability."