Colin Knox said his son "touched many lives"
Karl Bishop, 21, has been found guilty of murdering a young actor outside a bar in south-east London.
During the trial the court heard how in May last year Bishop stabbed 18-year-old Robert Knox five times "out of revenge".
Robert's parents, Colin and Sally, explained through victim impact statements what the death of their son had done to their family.
On 24 May 2008 the lives of many people changed beyond belief. It was on that day my son, Robert Knox, was taken from this earth. He was taken in the most cruel way possible.
Writing this statement is so very hard to do. Thinking about your first-born son and all that he was and did brings back all sorts of memories. The intensity of his absence is sometimes unbearable. Living my life without my son in it is like having a daily nightmare.
Those people that have nightmares will wake up in the morning and say, 'Thank God it was only a nightmare' and their life returns to normal. The opposite is my new way of life. I wake up to the fact that my son is not here on this earth for me to hug, kiss, laugh with, talk to, text or phone him. I won't get to see him become engaged and go on to get married.
I would have loved nothing more for Rob than for him to have a successful career, to be happy in marriage and for him to bring up his own children. Robert was always playing with young kids and babies, when they were in his company. He would have made a superb father.
Living day-to-day is quite hard. My children were and still are the meaning of my life. Every day since 24 May, not a day goes by where I don't cry for my son. It could be at my desk in work, on a train, watching TV or even in bed. There are nights that I lay in bed for hours not being able to get to sleep.
My life has totally been ruined. Rob my first born son. When he was born and he came home to his first house, I took him in my arms and walked him into the garden. He was wrapped in a little blanket and I looked down at him and said "Robert, welcome into our life. I will love you and I will promise to take care of you and protect you". I have done so for 18 years of my life and those 18 years were Rob's life.
I never had the chance to say goodbye to my son. What I had to do to say goodbye to Rob, was to go The Chapel of Rest, at Farnborough Hospital.
As I said my farewell, I bent down to kiss him on his forehead. He was cold, very cold. There was no body heat, body heat that I had always felt when I had ever hugged or kissed him.
You can never comprehend the loss or hurt caused by the death of a child, a child, which was wanted, carried for nine months and encouraged and supported through childhood to a young man.
As a parent you hope and believe that you will outlive your children, and although you appreciate that in some instances this is not possible due to illness, it is crueller when their life is taken away by the actions of another person.
I really wish I could remember the last moment I spent with him, that last look, but this was cruelly taken away from me when he died. It's just a blur. If only I could turn back the clock, give him one more hug, take one more look at his face, tell him how much I love him.
No-one can understand the panic and fear of what I was going to find when I got down at The Metro Bar. When I saw Jamie in total desperation, covered in blood, I felt sick and frightened for what I would find. I wanted to be with Jamie and comfort him but I needed to get to Rob. All I could think about was being with and seeing Rob - letting him know I was there, with him.
The wait in the hospital was so long, part of me knew but didn't want to believe Robert was dead, before we were told officially.
I will never forget the worst moment in my life when a police officer and a doctor walked into the family room and told us that Robert had died. The moment they walked in I just knew. I wanted to die myself, I couldn't believe it. They were talking about my boy, a young man who hours earlier had been chatting and laughing in the kitchen before going out.
It was the longest night, what could you say, what could you do? We were all numb and totally shocked. No words can explain the feeling of losing your son in such an unexpected way, his life taken away by the actions of another person.
I cannot explain what it is like living without Robert, the hurt of not being able to have a chat with him, not being able to cook and look after him. I miss him so much, I wish we could laugh together again, moan at him for being untidy, lying in bed, the normal things in life.
Losing Robert has changed our lives forever, we will never forget him and although we miss him every day we will always have the milestones of Christmas, his birthday and the anniversary of his death, to overcome.
As a mother and parent I can never forgive the person responsible for taking my son Robert's life, or the devastation that has been caused by these actions.