A son who watched his mum being sexually assaulted and stabbed to death on Wimbledon Common has said that he is “exploring reopening” legal action against the police.

Alex Hanscombe believes officers could have prevented her death along with a double murder in Plumstead which came just a year later.

Rachel Nickell, 23, was walking with her two-year-old son Alexander and their dog on Wimbledon Common on July 15, 1992, when serial sex offender Robert Napper lurched from bushes and attacked her.

She was stabbed 49 times and sexually assaulted in front of her son who was found pleading with her to wake up by a passer-by.

A lengthy police investigation to find the perpetrator followed, and 32 men were questioned in connection with the killing.

Colin Stagg, who was accused of killing Rachel, became “the most hated man in Britain” when he was wrongfully charged in 1993.

He was later acquitted in 1994 – and the case went cold.

In 2002 the case was reopened and on December 18, 2008 Napper pleaded guilty to Rachel’s manslaughter on the grounds of diminished responsibility.

Alex told The Sun newspaper: “In 2008 the police admitted they made mistakes and should have sent Napper to prison before he killed my mother, but they were not held accountable.

“We’ve had our lives turned upside down but never been compensated with a penny for her life. That is why we are exploring reopening legal action against them. We want to put pressure on them.

“If they hadn’t made the mistakes they did then we feel my mother would still be alive. It is not about the money for us, it is about a recognition of accountability.”

Alex also made the claim that racism may have played a part adding that: “If my father and me had looked like Hugh Grant, we think detectives would have treated us differently.”

Napper was already detained at Broadmoor High Security Hospital in Berkshire when he admitted to killing Rachel for a double murder in south east London in 1993.

He had stabbed and sexually assaulted Plumstead mum Samantha Bisset and her smothered her four-year-old daughter Jazmine.

Alex and Andre told The Sun that they believe that these deaths could have been prevented if police had acted on a tip-off from Napper's mother in 1989 after he apparently confessed to raping a woman on Plumstead Common.

Napper is also believed to be the "Green Chain Rapist" after a series of attacks took place in a four-year period ending along pathways in south east London.

After being sentenced for Samantha and Jazmine’s deaths, Napper was ordered to be detained at Broadmoor indefinitely with the judge adding that it was unlikely he will ever be released.

He also admitted to two other rape charges.

Speaking to Good Morning Britain, Alex’s dad Andre said: “For us the main point to make is that the system didn’t work, the institution failed to function and the person who should have been stopped in 1989 went on to commit even more horrendous attacks.

“And even though on a personal level, all the officers we came into contact with we could tell were doing the best they possibly could, from an institutional level it was a disaster.'

A spokesperson from the Met Police said: 'The Metropolitan Police Service has apologised unreservedly for the failings in the investigation into Rachel Nickell's death.

“Following the identification of Robert Napper, the Met's original investigation was the subject of a thorough and independent review by the then IPCC.

“We accept that more could have been done to have prevented a number of very serious attacks carried out by Robert Napper.

“The Met has made it clear to all those affected, including the family and friends of Robert Napper's victims, that we deeply regret the fact he was able to carry out these dreadful acts.

“Since the murder of Rachel Nickell the Metropolitan Police Service has significantly changed how it investigates murders.

“This includes the development and professionalisation of police training, new forensics techniques and closer liaison with the Crown Prosecution Service.”