Baroness Lawrence will not lay flowers on her son Stephen's grave in Jamaica later this month.
She used to go there every year to mark the anniversary of his death, but it is now 25 years since he was fatally stabbed by a gang of racist white youths for no other reason than because he was black.
Two lives ended with that brutal murder at a bus stop in South-East London on April 22, 1993: her 18-year-old son's and hers — or, at least, hers as she knew it.
Doreen has campaigned tirelessly to bring his killers to justice in the quarter of a century since, and two of them have been convicted, reports Daily Mail.
This 25th anniversary will be marked with a memorial service and a concert, after which Doreen wants "to draw a line".
"I can't keep doing this," she says. "I just want time for me — time to reflect.
"I've been on the go for 25 years. I haven't stopped. I don't think I've even completely grieved for Stephen.
"If you spend 25 years fighting for justice, where do you find the time? There isn't any.
"You pick up your grief and put it down; pick it up and put it down because there is always something you need to do.
"I went to his grave last year. His photograph was all worn, so I brought a new one, laid flowers and did the things I needed to do.
"I sat with him, telling him what's been happening — what his niece and nephews have been up to.
"In your head, you know he's not hearing you. You know he's gone, but it doesn't stop you talking. It's a way of just trying to get something out.
"I used to go every year. I know I can't do that any more. I have my other children [Stephen's younger brother Stuart, now 40, and sister Georgina, 35] and my grandchildren."
Stephen is buried in a peaceful plot overlooked by coconut and ackee trees next to his great-grandmother.
Doreen, now 65, spent the happiest years of her childhood with this decent, deeply loving, woman before she joined her mother in England at the age of nine.
She knows her grandmother, who called her Joy, would be hugely proud of all she has achieved.
At the opening ceremony of the 2012 Olympics, Doreen was invited to carry the flag in recognition of her tireless work on issues of social justice with the charity she set up in her son's name, to prove his death at least made a difference.
The following year she was made a life peer, and two years ago the new Chancellor of De Montfort University, Leicester.
"I remember, when I became Chancellor, standing there thinking: 'If my grandmother could see me now.'
"But I'd give all of this up . . .' Her eyes sweep around the grand, black marbled office that overlooks the Palace of Westminster.
"Stephen is much more important to me than this. I'd love to know what he'd have been like. Those are the sorts of things I'm always thinking about. He'd have been 43, a grown man with a family.
"What would they be like? What would he be like? Would he be working as an architect? That's what he wanted to do. He'd done some work experience before he died. I've still got those drawings.
"Stephen used to say to me: 'Do you know what your problem is, Mum? You care too much,' when I'd tell him to be careful.
"I'd like to hear those words again — hear him telling me what's happened at school.
"You don't realise how precious those things are at the time because they're just ordinary, everyday things. You expect them to be there all the time. Now you look back and . . ." she shrugs.
"That's why it's so important for me to let my children know I'm there and I'll do whatever I can for them. Otherwise, what else is there?"
Doreen searches my face for an answer. She has been accused in the past of lacking emotion, of being aloof. She tells me she "doesn't like exposing myself" so tries to put on a "poker face". But 25 years is a long time to suppress your feelings.
Today, talking to the Mail, she is often close to tears. "I find myself getting ever more tearful now, hence why I'm drawing the line," she says.
"I can't remember when I was last really happy. Since Stephen's death, there are little pockets in your life where you can say: 'That's a really good thing.' Like when my granddaughter was born or when my seven-year-old grandson dances in front of me.
"You're happy with your grandchildren. You can laugh and play with them, but that stuff — that hole — it's there and you can't get rid of it.
"I get on with life but the happiness you should feel, I don't think I've got that. I haven't got that. It's been a hard 20-odd years."
Indeed. Doreen's marriage to Stephen's father Neville collapsed in 1998 under the intolerable pain of their son's death.
So much so that they sat apart at the 2012 trial that saw two of Stephen's killers, Gary Dobson, 41, and David Norris, 40, finally brought to justice.
Doreen was only 40 years old when her son died but she has never had another relationship.
"Neville and I were two different people after that night," she says. "They say a tragedy like that either pushes you together or pulls you apart. The latter is exactly what happened.
"Neville seemed to believe this thing had only happened to him and not to the rest of us. He went off for six months in 1994 and then for a year."
It was, as she says, a "difficult time". So much so that Doreen doesn't wish to speak further about it.
"We can't know how life would have been without Stephen's murder, but I do know I felt alone. I was alone.
"There were two children and I had to be there for them. If they wanted to shout and scream, it was me they were shouting and screaming at.
"Now I get home in the evening and just collapse.
"Of course I'd like to share my life with someone. Who wouldn't? You want to be able to share things with someone, talk to them, have that one-to-one with somebody. But I think my name goes before me."
Dobson and Norris were finally convicted 19 years after the murder when new DNA and fibre evidence linked them to Stephen's murder.
Dobson was sentenced to serve at least 15 years and two months while Norris was given a minimum of 14 years and three months for what the judge, Mr Justice Treacy, said was "a terrible and evil crime".
He urged the Metropolitan Police to continue the investigation, but the three other killers, who were with Dobson and Norris that night, remain free.
Doreen last met the officers working on the case at the end of February. She doesn't believe they have a single significant lead to go upon.
Police were so slow to act in the days and weeks following Stephen's murder that vital evidence was never recovered.
These initial failings led to the Crown Prosecution Service (CPS) deciding in 1993 that there was not enough evidence to secure a conviction and the suspects were released.
A subsequent inquiry into the handling of the case, chaired by Sir William Macpherson, found the Metropolitan Police were institutionally racist.
"If they'd done all they should do in that first investigation, none of them [Stephen's attackers] would be walking the streets," says Doreen.
"In their eyes, Stephen was just another black boy, so they did nothing. But Stephen wasn't just another black boy: he was my son who had a future. I've had to make sure they haven't forgotten that.
"But now I don't think they have any more lines of inquiry. They say they're carrying on the investigation, but carrying on doing what? If they've come to the end, they should be honest — say they've come to an end and stop.
"I think they're carrying on pretending everything's fine because they don't want to hear what I'll say if it is stopped.
"As Stephen's mother, I think all of the gang should be behind bars spending time for murder.
"But it's six years now since those two convictions and I'm very conscious that the money for the investigation is coming out of the public purse.
"Had the police done their job properly in the first place we wouldn't be here. But they were incompetent and racist. They are the reason we are here today."
Doreen still keeps a running shirt and a cream, crew-neck jumper that belonged to her son. She last saw him alive on April 20, 1993, when she left for a field trip to Birmingham as part of the humanities degree she was studying as a mature student.
"I said: 'I'll be back in a couple of days.' He said: 'Bye Mum,' and you're through the door. You're not leaving thinking: 'This is the last moment I'll see my son.'
"It was very casual. That's what really sticks in my mind — how ordinary it was.
"Now, whatever happens, I always try to remember not to take my children for granted. Cherish the memories, whatever they are.
"I've got a scar here on my lip." She points to a barely visible mark. "The baby powder used to be in a tin container and, for whatever reason, Stephen threw it at me when he wasn't even a year old. That's a memory that isn't a sad memory."
Doreen had returned from her trip and Stephen's dinner was in the oven when she began to feel anxious that he wasn't home by his 10.30 pm curfew.
Ten minutes later, there was a knock on the door. A neighbour was there to tell them Stephen had been attacked. Nothing was the same from that moment on.
"I didn't think it was serious," Doreen recalls. "That's the last thing on your mind. You don't think your son is going to die.
"We got to the hospital not knowing, and, eventually, when the doctor and nurse came out, it was like watching a drama play out in front of us."
She remembers the doctor saying: "I'm sorry to inform you that your son has died." After that, they took them to see him.
"He had a sheet up to his neck, so the only thing you saw was his face. He had a gash, a deep cut on his chin. It was a funny colour. Stephen had my complexion — maybe a bit lighter. He just looked as if he was sleeping. He didn't look angry."
This is the first time Doreen has spoken publicly about this in 25 years and for a moment she is back there in that hospital room. She breathes deeply to collect herself.
"Things had gone blank in my head because you just can't believe it. You say: 'That's not true, that's not true.'
"You just stand there and nobody's saying anything to you. Nobody's explaining what has happened — what he came in with, what they did — and if they did explain, I can't remember.
"You're just thinking: 'Why would something like this happen?' Then Neville and I were just left.
"You were in the hospital thinking: 'What am I supposed to do now? I suppose I'd better go home.'
"You don't know what to do. Nobody's telling you anything, so you're just lost."
Such was Doreen's distress, she also doesn't remember if her husband comforted her.
"I don't think he ever did," she says. "I think it was the shock.
"I think we got home and Stuart was up, so we had to tell him. You're telling your 16-year-old son that his brother is dead. That's something I'd never want to do ever again."
The anguish of that night is writ large on her face.
"That first Christmas after Stephen's death, Georgina bought two presents for everyone: one from her and one from Stephen. She was only 11 years old. Even now, when she writes me a card for Christmas or Mother's Day, she includes Stephen's name."
Christmas remains a particularly difficult time. There are too many memories of happier family celebrations when Stephen was alive and she was married.
A deeply Christian woman, Doreen has questioned time and again how a benevolent God could have allowed her son to suffer as he did.
"I think of how he shouted out when they stabbed him, the pain he would have felt."
She pauses to collect herself.
"After Stephen died, going to church was very difficult," she continues. "The question I asked is: 'Why weren't You there to protect him?'
"I used to go each week. Stephen went to that church. He grew up there at cub scouts and doing drama stuff. The first Sunday of each month they used to have parade days and he'd want me to get to church early because he always wanted to carry the flag.
"So, after he died, that's where I would sit and, in my mind's eye, see him with the flag or doing some drama.
"As soon as the service was over I'd leave; I didn't want anybody talking to me. They couldn't give me any comfort. I'd get tearful and I didn't want that — I don't like exposing myself. I now believe that those circumstances at the time made me draw into myself."
Today, Doreen is no longer the person she used to be.
"Before, I used to go out with friends. We talked a lot and we'd go out in the evening," she says. "That doesn't happen any more.
"Whether or not it's because they didn't know how to deal with me, or whether it's because I was too focused and concentrated on what I needed to do and didn't notice, that's a question I can't really answer."
When the CPS refused to bring charges against Stephen's killers, insisting that there was insufficient evidence, his parents launched a private prosecution of their own — the first in modern British legal history — against Dobson and two other suspects, Luke Knight and Neil Acourt.
This extraordinary determination and the absolute refusal of Stephen's parents to accept the judicial system's decision is examined in a landmark BBC1 three-part series by BAFTA and Academy Award-winning documentary makers James Gay-Rees, Asif Kapadia and James Rogan.
For the first time, every aspect of one of the longest, most complex and mishandled murder investigations in Metropolitan Police history will be explored, including the ensuing murder trial which began at the Old Bailey on April 18, 1996.
All three men were acquitted after Mr Justice Curtis ruled identification evidence from Stephen's friend Duwayne Brooks, who was with him when he was attacked, was inadmissible.
At the time, Doreen collapsed. "All I remember was being taken up through the back of the court in a chair and being put in a car. I don't remember getting home, I was so hazy.
"The doctor came to see me. I was in a bad way. I was so shocked we weren't given an opportunity to present the case to the jury. I was convinced they would be convicted and go to prison.
"The worst part was that the judge instructed the jury to bring a not guilty verdict, which meant those boys could never be charged again [because at the time a defendant couldn't stand trial twice for the same crime]. If it hadn't been for the front page of the Daily Mail, they might never have been."
In February 1997, the day after an inquest into Stephen's murder delivered a verdict of unlawful killing "in a completely unprovoked racist attack by five youths", this newspaper identified the five white racists on its front page and accused them of being murderers.
It invited them to sue if it was wrong. They never have, but the furore that followed that headline — with calls for the Mail's editor to be jailed — had profound consequences.
"What the Daily Mail did was fantastic for exposing those individuals for who they are," says Doreen.
"That was a poignant moment for me. Before that, our faces were out there, but Stephen's killers could just get on with their lives and nobody knew who they were. Suddenly, there was nowhere for them to hide.
"Without that front page I felt we were being criticised the whole time. How dare you take out a private prosecution? How dare you criticise the police?
"Having that front page was like opening the whole country's eyes: this is what the family has been going through and these are the ones you should point your anger at — not us."
The Macpherson Inquiry followed, and in 2005, following a campaign by the Mail, the double jeopardy rule — which prevented suspects being tried twice for the same crime — was scrapped by the Home Secretary David Blunkett.
Doreen never gave up her fight for justice. In November 2011, the trial against Dobson and Norris began following a review of forensic evidence.
"If we hadn't had those convictions, I'm not sure what state of mind I'd be in," she says. "If you'd spoken to me ten years ago you'd have found me very angry still, but I don't think I'm as angry as I used to be.
"You can't walk around angry all the time because it just eats away at you. I've got far too much in my life now for that.
"I've spent the past 25 years doing things for everyone else; now I need time for me.
"I used to be able to walk down the street and have a conversation at the bus stop without people always saying: 'Are you Stephen's mum?'
"One time I said no — and I felt so bad because I felt as if I was denying him. But sometimes you just want to go to the shops and do whatever you want to do without someone stopping you to talk.
"But those other men who killed Stephen and haven't been convicted will always have everybody's finger pointed at them. They don't have a future.
"As for me, the time's come to spend time with my children and grandchildren.
"I want time to be me again — yes, still grieve properly for Stephen, but live my life and be happy and feel joy again."