A campaigning grandmother says she and her family are frightened that her daughter’s killer will return to the island.

Diana Parkes wants to ensure the man who bludgeoned her daughter Joanna to death, hitting her 14 times on the head with a claw hammer, will never step foot in the Isle of Man again. Joanna grew up in the island.

Robert Brown is due to be released from prison next year after serving half his 26-year sentence for the manslaughter of his estranged wife.

The couple were going through an acrimonious divorce when he carried out the brutal attack at the marital home in Ascot, Berkshire, in October 2010 – within earshot of their children playing in the TV room nearby.

Brown put her lifeless body in the boot of his car, pulled out the CCTV and telephone cables, told the children to get into the car and drove to his pregnant girlfriend’s home and left them with her.

He then dumped Joanna’s body in a grave he had spent months digging in Windsor Great Park.

Following a two-week trial, a jury acquitted Brown of murder – a decision with which Joanna’s family are still struggling to come to terms.

After her daughter’s death Diana took Joanna’s two children Katie and Alex, then aged only nine and 10, into her care at her home in the Isle of Man and has dedicated her life since then to keeping them safe.

Now the family fear Brown could come to the island when he is released from prison next year.

Speaking from her home in Sulby, Diana said: ‘We all believe this guy is a psychopath. He’s really, really dangerous.

‘We are frightened he will come here. My son James who lives in the island is also worried.

‘Brown and Jo used to come here, so he knows the island and our home.

‘He will blame everyone else but himself. He’s shown no remorse whatsoever.

‘He wants to tell the children why he killed their mother. His children don’t want anything to do with him.’

Diana, 82, believes the jury’s decision would have been very different if the prosecution had outlined to them details of the coercive control Joanna had suffered and what she had endured during her bitter divorce battle.

Instead, they accepted the defence case that the former British Airways pilot had suffered from ‘adjustment disorder’, a temporary mental illness he blamed for the attack.

She said: ‘If the prosecution had brought in details of the divorce he would never, ever have been given manslaughter.

‘It was horrendous. Brown sat in jail for six months before his trial planning his ridiculous defence.

‘Victims and their families have no right of appeal. We are stuck with such an appallingly perverse outcome of this trial.’

Diana is keen to point out that her daughter’s killer is not being released early.

She instead hit out at the system that allows offenders to leave jail after serving just half their sentence.

Brown will be on licence for 13 years upon his release next year.

But Diana and her family are not satisfied with Probation Service assurances about how Brown will be monitored during that time.

They want to make it a condition of the licence that Joanna’s killer is barred from visiting the Isle of Man.

She said they initially got nowhere with the Probation Service.

But that changed when she appeared on Radio 4’s Women’s Hour alongside Camilla, Duchess of Cornwall, who was inspired by Diana’s story to become a passionate campaigner against domestic abuse.

Diana, who set up the Joanna Simpson Foundation in memory of her daughter to support children affected by domestic abuse, said the intervention of Nicole Jacobs, Domestic Abuse Commissioner for England and Wales, went on to prove vital in getting their concerns heard.

A victim liaison officer will be coming to the island next month.

Katie and Alex, aged 20 and 22 and in their final year at university across, will be at the meeting to discuss what licence conditions they would want to see imposed.

They are hopeful that conditions can be agreed excluding Brown from the Isle of Man.

‘If he was seen here he would go straight back to jail,’ explained Diana.

The Joanna Simpson Foundation is raising funds to pay for a domestic abuse counsellor at the Children’s Centre in the island. It is holding a second Turquoise Ball in a marquee at the Equestrian centre at Ballacooiley, Ballaugh, on Saturday, May 14.