NEW DELHI: The mother of a British teenager who was raped and left to die on a Goa beach five years ago has blasted India's "rubbish" legal system over the stalled trial into her daughter's death.

Scarlett Keeling was only 15 years old when her bruised and half-naked body was found on a beach in the Indian resort state of Goa in February 2008.

Two men were arrested and charged with homicide several weeks after the attack on the popular Anjuna beach in the coastal state which has long been a haunt for Western tourists.

But five years on, their trial has come to a standstill and the pair are out on bail in an echo of a wider malaise in the notoriously sluggish Indian justice system.

In an interview with AFP, Scarlett's mother Fiona MacKeown expressed her exasperation at the delay, saying she will not be at peace until she has secured justice for the youngster.

"The system is just rubbish," she said by phone from her home in the county of Devon on the west coast of England.

"It's ridiculous that it's now five years and we are still waiting."

The delay is another embarrassing example of India's failure to deliver timely justice for victims of sex assaults, with anger still smouldering over the deadly gang-rape of a 23-year-old student in Delhi in December.

Scarlett's death also attracted international headlines, highlighting the dark side of a tourist destination still seen by many as a hangout for hippies.

Since the trial began in 2010 at the children's court in Goa's state capital Panaji, proceedings have hit numerous obstacles.

The court has not had a full-time judge since 2011 and the public prosecutor withdrew from the case two years ago saying he did not have enough time to devote to it.

Since 2012, the court has met just once a week as it struggles to clear a massive backlog of cases.

Police initially dismissed Scarlett's death as an accident but opened a murder probe after MacKeown piled pressure on local authorities, pushing for a second autopsy which proved that she had been drugged and raped.

But the two defendants, Samson D'Souza and Placido Carvalho, were not charged with rape or murder after officers from India's Central Bureau of Investigation (CBI) said they lacked sufficient evidence to indict them.

Instead they were charged with culpable homicide, using force with "intent to outrage her modesty" and administering a drug with intent to harm.

Police allege that Scarlett was given a cocktail of illegal drugs and dumped unconscious in shallow water where she drowned, a theory MacKeown dismisses.

"I don't believe for a minute that she was left to die," she said.

"Someone was brutal with her and held her face down hard in the water to kill her."

The family was on a six-month holiday to India when MacKeown and her other daughters went on an excursion to the southern state of Karnataka, leaving Scarlett in the care of a Goan family.

MacKeown came in for heavy criticism back home for leaving her daughter without parental supervision.

Five years on, MacKeown is back home in Devon, with her remaining children and her "happy, nurturing" daughter never far from her thoughts.

"She loved life, she had so many dreams. She wanted to study art, she wanted to play in a band," she said.

"We miss her so much, she was my oldest girl and she was so good with her younger brothers and sisters."

She buried her daughter's body only six months ago, when it was finally returned to her by Indian authorities after a long bureaucratic wrangle.

MacKeown's Goa-based lawyer, Vikram Varma, told AFP the ongoing Delhi gang-rape trial which is taking place in a fast-track court held important lessons for the rest of India's police and judicial establishment.

"In Delhi, police arrested the culprits within days, not weeks. And the court has promised a verdict soon. So clearly when we set our minds to it, we can deliver justice within a reasonable time frame," he said.

In Devon, MacKeown says she watched footage of the anti-rape protests in India with a sense of hope.

"I think it's great that the younger generation is standing up and saying they have had enough. All women in India face the threat of this rape culture," she said.

"My daughter was a victim of this too and it's time to put a stop to it. I won't be at peace until someone is punished for what they did to her."