The mother of a 'true gentleman' who died after a 'one punch' attack at the Parklife Festival in Manchester 10 years ago has issued a fresh plea for the public's help to bring the family closure.

Robert Hart, who was just 26, was at the festival in Heaton Park with his girlfriend and friends when he was punched in the crowd as US rapper Snoop Dogg was about to take to the stage. He suffered a catastrophic bleed on the brain and sadly died in hospital five days later.

About 70,000 people were at the festival that weekend, but to this day, the man who punched Robert has escaped justice. Detectives at Greater Manchester Police have also issued a new appeal, saying allegiances change with the passing of time. A dedicated email address for people to submit information has been launched.

In an emotive appeal today, Robert's mother Elaine Hart told how the family prayed at his hospital bedside as he lay in an induced coma. She described the attack as 'completely, completely unnecessary' - and told how Robert's future dreams had been taken away in an instant.

"We've still not come to terms with it, that Robert won't come walking through the door with his jokes and with his warmth and with his laughter. He was such a loveable, happy boy. He was very funny. He made everybody smile. He was a lovely, lovely boy," Mrs Hart told BBC's Crimewatch on Tuesday.

"His teacher used to say that before they saw Robert, they could hear him because of his laughter. Our relationship was good - there was a lot of love."

Mrs Hart recalled Robert's love and kindness, saying he whisked her away for an impromptu holiday to France - memories she said she would cherish forever. "He took me on holiday," she said. "He just said 'I'll take you on holiday, mum'. And I said, 'ah Robert, that's so kind. Where shall we go?"

"He said 'you choose - Paris?' And he took me to Paris for the weekend. Because of his love of art, we went to the Louvre. That memory of Robert taking me, aged 24, to Paris - that will always stay with me."

Robert, the youngest of four children, grew up in Rainow, Macclesfield and went to primary school in the village before attending Fallibroome Academy. He then went on to study art and design at Liverpool John Moores University.

The attack happened at around 9pm on June 7, 2014. Robert regained consciousness in the crowd but was taken to hospital from the festival's medical tent. "We all prayed and prayed," said Mrs Hart. "That is something that I will never forget. He had bruises on the back of his hands where he protected his face."

"This attack was so completely unnecessary and that punch was so brutal and forceful that it completely knocked Robert out. It caused the bleed on his brain. He never returned home; he died five days later."

"We have to continue with our lives while Robert lies in Macclesfield Cemetery and that is very hard. I would like to think that he would have followed his dream - wherever it took him." Mrs Hart added: "I would like Robert to be remembered as my son who had a huge sense of humour - very kind and a true gentleman."

Det Sgt Clare Smith from GMP stated one punch 'can take lives'. "The person responsible may well not have been aware of the fatal impact that their actions had because they left the scene immediately afterwards," she said.

The suspect is described as a mixed race man aged in his mid-20s and around 6ft 2in tall with short dark hair shaven at the sides and muscular build. At some point during the festival he was seen with a white woman aged in her mid-20s with shoulder-length blonde hair possibly wearing a pink T-shirt.

Det Sgt Smith expressed hope: "We are hopeful that those who didn't feel comfortable talking to us in 2014 may now feel brave enough." If you witnessed this attack or someone confided in you about what happened afterward we would like to hear from you.

"It remains unsolved; it's an ongoing investigation," she continued. "Someone out there will know who is involved; we are appealing directly for them today do right thing." A £50,000 reward remains available for information leading to justice.