A couple whose son was left severely brain damaged in a hit-and-run want a change in the law for sentencing dangerous drivers.

They are outraged the culprit, who drove off, leaving 20-year-old Graham Phillips fighting for his life, only faces a two-year maximum jail term.

The victim, a Leicester University student, was crossing Evington Road, in Evington, Leicester, when he was mown down by 22-year-old Rajesh Khunti in the early hours of September 22, 2007.

Graham was left with injuries described at Leicester Crown Court as "being trapped inside a body that simply doesn't function".

Judge Christopher Metcalf shared his parents' concerns, saying the maximum penalty imposed by Parliament for the charge of dangerous driving was "woefully inadequate".

He said: "One can't help feeling sorry for the family of this boy, wondering what on earth the system is that allows this to happen. This court has told Parliament about it hundreds of times – and what a ridiculous level of sentence this offence carries."

Yesterday, Khunti, of Glen Street, Belgrave, admitted a charge of dangerous driving.

He was remanded into custody and will be sentenced on March 17.

Graham's mum and dad, Donna and Roy Phillips, describe the jail term Khunti is likely to receive as an "insult" to their formerly sports-loving son, whose life has been shattered.

Mr Phillips, 59, said: "My son is going to be permanently disabled and will be lucky if he talks again.

"A maximum sentence of two years, for someone who didn't even have the decency to stop after running him over, makes me sick to my stomach.

"The law urgently needs to be changed to reflect the seriousness of the crime, otherwise there will be no justice for other families in this situation. It's no deterrent.

"A harsher punishment might make people think twice."

Graham, of Tennyson Street, Highfields, Leicester, was saved by the skill of neurosurgeons, but is now bed-ridden, unable to speak and can barely move unaided.

Khunti abandoned the Honda Civic he was driving after the collision.

He was arrested the next day, but it was only when he entered his guilty plea – on the day he was due for trial yesterday – that he even acknowledged being the driver.

He also admitted failing to stop after an accident and having no insurance.

Mr Phillips and his 54-year-old wife, of Weybridge, Surrey, rushed to their son's bedside after the accident.

After many months of hospital treatment in the UK, Mrs Phillips, who is American, took Graham to Austin, Texas, for specialist treatment.

She is looking after him there in a house with help from relatives and a carer. He is making some progress and is now starting to use a communication device.

He has to be fed by a tube in his stomach, although he can manage some liquids, but he needs 24-hour care.

Mrs Phillips said: "We were so focused on Graham's recovery – it's taken every last drop of our energy – that we didn't even think about the offender until now."