At drug dealer Nicqueel Pitrora's sentencing hearing, Daniel Spargo-Mabbs's mother Fiona delivered a heartbeaking address recalling how she and husband Tim helplessly watched their son die and explaining their struggle in the aftermath of his death. Below we publish her words in full.

"Before we try to tell you about the impact of losing Daniel, we need to try to tell you about the impact of having Daniel in our lives. Words are deeply inadequate for both tasks, but are all we have. 

"Dan used to make me a cup of coffee every morning. He used to chat to me while I got ready for work and he got ready for school, sitting in the bathroom while I did my make-up, following me around to finish telling me something, or asking what I thought about something. 

"Before he died he'd kept buying us all cream eggs in his personal quest to find the cheapest deal. It was always three for something, so he ate one himself, and gave one each to Tim and to me. We kept the last one he'd given us on the windowsill for months. 

"He had a very strong sense of justice, of right and wrong, and a very big, generous heart and conscience. He ran little errands for the elderly ladies on his paper round. He was a member of Amnesty International. He walked barefoot from Croydon to central London to raise awareness of the plight of children in the developing world unable to afford shoes. 

"Shortly before he died, he'd been accepted as a bone marrow donor. He was very disappointed to find he was unable to give blood until he was 18. He carried an organ donor card in his wallet, but of course his organs were no use to anyone by the end. 

"Dan was the one who'd always be happy to help out, especially with practical things, checking the tyre pressure on the car, fixing the dodgy fence, fiddling with cables behind the new blueray player. He liked a challenge. 

"He was well and widely loved at school by both pupils and staff, and was overwhelmingly voted Prom King in summer 2013. Dan was ridiculously funny; he was quirky, curious, intelligent, engaging, charming, infuriating, loving and infinitely, enduringly lovable. He was an enormous, dynamic, enriching and life-affirming presence in our lives. 

"Perhaps it was his curiosity and desire to experience all that life had to offer, that led to him making this one fatal mistake. I don't know that we'll ever know. But it was just one, very bad decision; A first and last time. 

"He was our son, and we love him, and would have given our lives in place of his. 

Your Local Guardian: Daniel Spargo-Mabbs

Daniel Spargo-Mabbs

"The drug that Niqueel Pitrora supplied on January 17 caused Dan's body temperature to rise to 42 degrees. Each of his internal organs and systems stopped functioning in turn over the next few hours, and by the time he was transferred to King's College Hospital that Saturday afternoon, his lungs, liver, kidneys, heart and circulatory system had all failed. We sat with him over the next two days and watched him slowly die. 

"He never regained consciousness, but we talked to him, held his hand, stroked his hair, rubbed his shoulders to try to get them warm. We found out after he'd died that he'd almost certainly suffered damage to his brain because his oxygen levels were so low when paramedics reached him, and they were unable to intubate immediately because the MDMA had caused his jaw to lock shut.

"At King's he was on a ventilator, kidney dialysis, continuous bloods and fluids to try to raise his blood pressure and help his heart to begin to work better, and there were so many drains and monitors and machines it was difficult to get too close to him, but we did what we could. 

"Because his liver wasn't functioning his blood wouldn't clot, and so wherever they'd had to put tubes in was continually bleeding. They'd put plugs up his nostrils where there were tubes, but the blood still seeped out slowly all the time. 

"His eyes weren't quite closed, and so they had to stick blue gel pads over them to stop them drying out. 

"He had to have emergency surgery to save his legs a few hours after he was taken into intensive care at Hillingdon, because pressure accumulating in his muscles meant the circulation was dangerously limited. On two further occasions they considered whether amputating his legs would improve his circulation, but both times it was decided that there was too much else wrong for it to make the difference needed. 

"By the final morning, the circulation in his legs and arms had been so reduced as a side effect of the last drug left to them to try, that his legs and arms had already died, there was no surgical option, and they had no choice but to switch the life support off. 

"It took just twenty minutes for him to die. We were all with him. I was holding his face, because it was all I could really hold that was still living. 

"After the beeps on the machine got slower, and then did the continual beep, to tell us his heart had stopped, I just couldn't let go of his face, because I knew when I did it would go cold, and then it wouldn't be warm again. 

"I held him for what seemed like ages. But then I had to let go. 

"At that point our lives fell apart completely. We're slowly trying to rebuild them into whatever our 'new normal' will be, but we've barely begun and have a very long and hard road ahead of us. 

"Physically, we are both taking tablets to help us sleep, but I still struggle to get off to sleep, to let go of each day. I hold out against closing my eyes, knowing when I open them another day will have gone, taking me further away from when Dan was still here. 

"The sleep I have is troubled and unhappy. I often wake up with my jaw clenched. And so I experience profound exhaustion. The stress has caused me to lose a significant amount of weight. I've cracked a tooth because of clenching my teeth so hard when I sleep. Tim is on anti-depressants. I'm receiving counselling. 

"When people talk about having an aching heart, having a broken heart, I'd always assumed this was metaphorical. I didn't know that it would be an actual physical pain. 

"In terms of work, my job is to manage a team of about 50 managers and teachers in Croydon Council's adult education service. On top of this full time job, I also chair a national network of family learning managers, and was leading on two national projects in January. 

"When Dan died, I was unable to function at all, or to work at all for over three months. I've been on a phased return for more than three months now, but have made no progress, am still unable to focus for more than an hour in a day, two at most, sometimes only twenty minutes, and some days I'm unable to do anything because I can't stop crying or get off the sofa. I can only attempt very low-level tasks. 

"My head is still so full trying to process and make sense of this thing that makes no sense, that I can't put it anywhere else for very long. 

"Tim has managed better with getting back to work, but still struggles so much some days that he has to leave early, and every day gets home totally spent and exhausted. 

"Jacob, Daniel's older brother, was meant to be going back to Kent University the weekend Daniel was in intensive care, for the start of his second term of his first year studying history. 

"Consequently he missed the first four weeks of term, and struggled when he went back with concentration and focus. He got almost straight Firsts in his first term assessments, but hasn't managed to repeat this since Daniel died. 

"He knows he copes by distracting himself, by pretending it hasn't happened, by thinking about other things, or going for a long bike ride. Sometimes this doesn't work though, the reality of losing his brother hits him, and he breaks down. 

"In most of the photos we have of them when they were smaller, over many years, Jacob has his arm around the shoulders of his little brother, and both have identical smiles. He is now an only child. 

"The impact beyond Daniel's immediate family has also been profound, and like a tsunami rather than a ripple effect, reaching far beyond family and close friends to the wider community.

"Our parents, our extended families, Daniel's closest friends, his girlfriend of over two years, his very wide circle of other friends at school and church, his school community, our church community, our friends and colleagues. 

"Too much and too many to be able to account for. His loss is far-reaching. 

"I still can't believe that this has happened. How can someone so full of life be there, and then just not be there? From time to time the reality of it comes into focus, briefly, like glimpsing something in the corner of my eye, and it's so unimaginably awful that I honestly think it'll destroy me completely, and I have to look away again. 

"The rest of the time it remains hazy, as if I have a vague memory of a lovely dream I had once, where I had a lovely son called Daniel. Or as if this present reality is a dream, a horrible dream, but I'll wake up sometime and get my real life back, where I have two lovely sons, a job I love, and all is well. But this haziness I hate as well as the unbearable reality, because in it any clear sense of the real Daniel is lost. 

"It feels like a double robbery, losing Dan in reality and in my head, which is all I now have. But to have a sense of the real Dan back, brings with it the awful knowledge that he's gone. There is nowhere to rest. 

"When you become a mother, from the first moment you know you're expecting a child, your identity, your energies, your focus are on that new little being, and such a massive part of who you then are, is being that person's mum, and is pouring an infinite quantity of love into that person. 

"I still have all that for Dan, but don't know what I do with it now. I don't know who I am, what's left of me, now that I can't be Daniel's mum. 

"And how can someone who has been such a massive part of me for more than sixteen years, as his mother - how can he not be here anymore, when I still am? What do I do with this love, this energy, this focus, this massive part of my identity? 

"It's like having a limb ripped off without an anaesthetic. It's like having an enormous gaping open wound. And it's not like either of these things. It's so, so much worse. 

"I would choose either of these things over losing my son. And this is the rest of my life on this earth. 

"I believe very strongly that Dan is safe with God, and that I will be with him again one day, and this does bring hope. But the despair remains in having to walk through each day of the rest of my life without him, because of this one bad decision. 

"Our prayer for Nicqueel is that he will be able to connect his actions with the consequences, that he will be changed by this, and that he won't waste the rest of his life continuing to do what he did that led to our son dying.

"Dan's life ended on January 20, and part of us also died then, but he has all the rest of his life ahead of him. He can choose to do good with this life, and that's our prayer."