James Sweeney wakes at night with tears streaming down his face. He can't stop thinking of his little grandson, even in his dreams.

The boy has been dead two years now but the pain is just as great.

He said: "The grief will go with me to the grave."

Mr Sweeney, a 71-year-old widower and a former general foreman in public works, has no favourites among his grandchildren.

He loves them equally but he mourns John Smith's death like the loss of a son.

Mr Sweeney was unable to hold back the tears when he spoke about the four-year-old. He said: "He was a little angel and I loved him.

"Every time we met he'd come running up to me shouting, 'Grandad, grandad,' and he would leap into my arms. We would hug and give each other big kisses.

"John was a happy-go-lucky lad, always smiling and lively. He loved playing with different toys and was always drawing or painting.

"He was never seriously naughty and I never had to say anything to him or scold him.

"He was a little boy, of course, and he'd be into everything. He got hold of my phone one day, pressed the buttons and dialled 999."

John, nicknamed Snodder by his family, was regularly taken by his parents to visit his grandfather at his home in Hallyburton Road, Hove.

Mr Sweeney said: "He was a clever lad. We once gave him a remote-control toy car. We thought it might be too difficult for him to master but he got the hang of it straight away."

When John was taken into care, Mr Sweeney was able to visit him at the home of the boy's foster parents three or four times a week.

That continued for 17 months but things changed radically when John moved in with the McWilliams.

Mr Sweeney understood it was important for John to bond with his prospective adoptive parents so he was prepared to wait for access visits.

But one scheduled before Christmas was postponed on the request of the McWilliams.

The couple told social workers that visits with people from John's past upset him and he often misbehaved before and afterwards.

John's family believe the opposite, that John was desperate to see them and that the McWilliams were lying to prevent relatives seeing John's injuries.

Mr Sweeney did not think the McWilliams were suitable parents.

He said: "I met them once. They kept themselves to themselves and didn't ask many questions. I just don't think they had enough experience to raise a child properly."

Mr Sweeney's last visit with John was postponed until late December but John died on Christmas Eve and he never got to see his grandson.

Mr Sweeney now visits John's grave at least twice a week and speaks to him. He gave him progress reports on the trial and keeps him up to date with family news.

"I tell him he shouldn't be there, where he is, that he should be with us."

Mr Sweeney cries at the graveside and remembers the boy's last words to him: "Ta, ta grandad. I will see you again."

He said: "I'll never get over what happened to John for as long as I live.

"It just shouldn't have happened and I'm very unhappy with social services."