The man wrongly accused of Rachel Nickell’s murder has condemned the Metropolitan Police’s decision not to compensate her son for failings in the case as “sick, but not surprising”.

Colin Stagg, who received a £706,000 Home Office award after spending 14 months behind bars, said Scotland Yard should make a goodwill payment after admitting it made errors and mistakes in not catching serial sex attacker Robert Napper years before Miss Nickell was stabbed 49 times on Wimbledon Common.

He said: “They have no shame. As a two-year-old back in 1992 Alex Hanscombe witnessed his mum’s horrible death.

“God knows what damage that trauma has caused him. But for nearly 20 years the Met covered up their appalling mistakes made before and after her death.

“Not only did they miss a glaring opportunity to catch her killer two years earlier, their fixation on me as the prime suspect allowed him to go on and murder another mum and her young daughter two years later.”

The Met said after “careful and detailed consideration” it had decided not to pay compensation to Alex Hanscombe, and his father – Rachel’s partner – Andre.

Speaking from his Roehampton home, Mr Stagg, 47, said: “These mistakes were criminal. Yet when given the chance to right the huge wrong done to Rachel and her boy they hid behind a legal smokescreen.

“They didn’t even have the decency to make a voluntary goodwill payment or cover his father’s legal costs in getting the Independent Police Complaints Commission (IPCC) to investigate.

“It makes me sick, but I’m not surprised.”

Alex Hanscombe, now 21, and his father forced the IPCC report into the case after Napper was convicted.

It found Napper should have been arrested for his serial sex offences known as the Green Chain rapes across south-east London in the 1980s.

But police eliminated him from their inquiries despite his mother telling them he had raped a woman.

They also failed to follow-up his failure to give a DNA sample, which would have identified him as the attacker.

This allowed him to murder Miss Nickell in July 1992 and butcher single mum Samantha Bisset and her four-year-old daughter Jazmine at their Plumstead home 18 months later.

Napper was arrested in 1994, and sent to Broadmoor prison after being found guilty of the Bisset murders a year later.

In November 2008, after DNA linked him to Miss Nickell’s murder, he pleaded guilty to her manslaughter on the grounds of diminished responsibility. He will remain in the secure mental hospital for life.

A Met spokesman said: "Andre Hanscombe’s lawyers wrote to the MPS seeking compensation but have accepted that there is no basis for a civil claim against the MPS.

“They now intend to pursue their claim in the European Court of Human Rights. There has already been a payment made to Alex Hanscombe from public funds for the impact of his mother’s murder.

“Having considered all relevant factors the Met has made the difficult decision not to compensate Mr Hanscombe or pay his legal costs."