More than three years have passed since their sons died in a horrific lorry crash in Australia, but the pain is still there.

Tears are shed every so often by Penny and David Standing, grief that is made worse by what Mr Standing insists is a miscarriage of justice.

The driver of the lorry which killed their son Peter, 21, and three friends walked free from court without a blemish on his record.

What the jury was never told was that Scott Pitkin, 28, was under the influence of illegal drugs, was speeding and that he had driven more hours than legally allowed.

The four friends died when an estate car they were travelling in was hit by the lorry on the Bruce Highway near Tully, Queensland, in Australia.

Pitkin's semi-trailer ploughed into the rear of the friends' Ford Falcon, which was stopped at a set of temporary traffic lights at roadworks.

It was midnight and clear conditions meant the traffic lights could be seen more than three miles back.

Townsville Supreme Court heard the road was in good condition and there were no potholes but Pitkin denied the charge of dangerously operating a motor vehicle causing death.

The jury was shown photographs of the trailer, which ended up on its side, and the Falcon, which was almost unrecognisable, its roof peeled forward.

The jury heard a taped interview in which Pitkin said he did not see the vehicle nor did he see several signs warning of roadworks.

None of the new evidence was put before the court and Pitkin was cleared.

It was left to a later Queensland coroner's court hearing to bring the matters into the public domain.

The coroner said there was clear evidence against Pitkin but he could not commit him for trial as he had already been acquitted.

Mr Standing said: "If the trial had been held after the inquest more evidence might have been available.

"In December 2000, two more young Britons were killed in identical circumstances - a truck went into the back of their car at roadworks on the same road.

"On this occasion, the truck driver acknowledged he had fallen asleep and he was convicted."

Mr Standing would like to see changes in the judicial process and he intends to write to Queensland's Justice Minister.

Mr Standing said he and the other families felt aggrieved and wanted a judicial review that would lead to safety improvements to prevent future tragedies.

He said: "Police told us it was very difficult to secure prosecutions against truck drivers because they have a very powerful lobby. They hire the best barristers.

"Each of us has had to deal with this tragedy in our own way. It affects you from time to time and Penny still gets weepy. We miss him."

Mr Standing, 52, of Amherst Crescent, Hove, remembered feeling as if he was in a dream when he heard of his son's death.

He said: "It was a nightmare. We didn't believe it and we couldn't take it in.

"Although the pain is still strong, the shock has been replaced with a determination to honour Peter and produce some good out of his death by supporting the causes he believed in."

Families and friends have raised tens of thousands of pounds through a memorial fund, which will be spent on homes for street children in Brazil, near to where Peter spent ten weeks helping the children before his death.

The Standings hope the home will stand as a testimony to his short but full life.

Peter, a former pupil at Cardinal Newman School in Hove, was taking a year out from studying geography at Swansea University to go travelling at the time of the crash.

He worked on the project with street children in Goiania, Brazil, before going travelling in Australia.

He died with his friends, brothers Martyn and Ben Hebblethwaite, and Timothy Skipp.

Peter's younger sister Jo also visited Brazil to help build the memorial home.

She said her brother came back a changed person after his trip there: "He was at home for three months and some of the things he said about Brazil were quite shocking.

"I can't change the fact he has died but I can try to focus the energy he had into doing something positive."

The building is called the Peter Standing Home and it provides a refuge for children to escape the cycle of living on the streets. They are taught new skills to refocus their lives.

Mr Standing said one home had already been built and a second had recently been completed.

He said: "We are doing this so something positive will have come out of his death.

"We are Christians and I think we derived quite a lot of strength from our faith to cope with what has happened."

He said he felt no bitterness towards the truck driver but he did feel a sense of injustice.

He said: "Nothing is going to bring back Peter but we feel very let-down by the Australian judicial system."

He and Penny drew great comfort from their daughters Kate, 28, who works as a YMCA housing officer, and Jo, 21, now living and working in Australia.

Dr David Skipp said his son Tim, a medical salesman, loved rugby and the two would often go to Twickenham for internationals: "I still feel his presence when I go there."

His wife, Dr Helen Skipp, a magistrate, said she thought about her son and his death all the time: "I wake up with it and I go to bed with it. But we are a positive family. Our daughter Joanna has just graduated as a doctor and is getting married next year and our son Ben is doing music at Oxford. I think Tim would be proud of us."

A memorial fund, Timios Trust, provides travel bursaries for people aged 18 and over to carry out practical services, including painting a hospital in Uganda. So far 49 people have benefited.

Mr Hebblethwaite, a garden designer, said he was angry that justice had not been done.

He said of yesterday's inquest: "That was the last chance to air our concerns.

"Australia is a wonderful country but I would say to all parents whose children intend travelling there, beware of the dangers."

Their eldest son Ben, a self-employed builder, had been happily married for three years when the crash happened.

His younger brother Martyn was studying at Swansea University.

The Hebblethwaite's surviving son Lawrence, 18, still intends to travel to Australia when he completes his horticultural studies.

A memorial fund in the brothers' names has contributed to the construction of school buildings in Africa and has helped disadvantaged children in the UK.