The tears are surprisingly near the surface even now; even after 20 years.  

It seems almost unbelievable that it all happened so long ago, and yet the awfulness of that summer morning when I found my baby boy Sebastian, dead in his cot, never wanes. The emotions can still flood back and hit me like a hammer blow.

Over the two decades since that day, other bereaved parents and experts have assured me that ‘the pain fades with time, but the love never does’. 

Precious moments: Anne cuddles her healthy baby boy, Sebastian, who died aged just four months

I have clung to that mantra through some very dark times, and it has helped. But as I remember the moment I helped my two older sons, Oliver (then four) and James (just two), say their last goodbye to their little brother, the tears still well up, my voice cracks, and the rawness of the pain still shocks me.

I’ve constantly tried to ensure that Sebastian’s life, of just four-and-a-half months, remains larger than his death - at least to his family. Of course, his loss in 1991, when I was a presenter on morning television, became huge news and the focus of a national campaign to help prevent cot deaths like his. A campaign that experts say has saved as many as 20,000 lives.

It always makes me look back with immense pride as well as grief. My little boy’s death was not in vain.

But when the family get together, as we did just a couple of days ago, this time to celebrate Oliver’s 24th birthday in a local Chinese restaurant around a big family table, I am always aware of Sebastian’s absence and I can’t help thinking what might have been had he lived.  

Grief: Anne and Mike Hollingsworth carrying their son's tiny coffin

I know exactly how he’d be. A tall, strapping lad with a rugby player’s build, strawberry blond hair and a slightly freckly complexion. That’s the child I used to envisage when I looked into his baby’s face.

Even after all this time, I know just where I’d pick up the conversation with him. I’ve had lots of imagined chats with him over the years. And I’ve many times fantasised how it would be if the past 20 years were just a horrible dream, and I woke up to find him living with us, just as ordinarily as his brothers.  

Please don’t think, for a minute, that I live in a constant state of mourning, like Miss Havisham, with a cobweb-strewn nursery upstairs and a penchant for the morbid and tragic. Thanks to my four other sons, I have always been determined to be a vibrant family of which Sebastian would be proud.

But while grief - I think - never leaves you, it does mature, like an old wine. Just very occasionally it actually tastes warm and comforting to indulge in, but it’s stronger than you think, and can knock you back unexpectedly.

One terrible, cruel feature of Sebastian’s death was that it happened on my eldest son Oliver’s fourth birthday.

One particular photo, too poignant to stick into any family album, sums up the sorrow of that day.

I haven’t seen it for years. It surfaced just a few days ago, when I was researching for a speech I was asked to give to the Foundation for the Study of Infant Death.

There, amid the reams of paperwork and reports, was the picture of Oliver, taken on the day he should have celebrated being four, but which became the day his little brother died and our world turned upside down.

It is of him wearing an enormous policeman’s helmet, looking more perplexed than happy at the events unfolding around him.

Breakfast favourite: Anne, pictured here with co-presenter Nick Owen, was at the height of her fame when tragedy struck

It had all started out so happily.

The children had all slept well and I’d had a lie-in until 7am. I remember thinking how lucky that Sebastian hadn’t woken early, because it gave me time to go into the big boys’ room and sing Happy Birthday to Oliver. Then I popped into the baby’s room.

I could tell immediately something was wrong. Sebastian’s arm was dangling through the bars of his cot and he looked strangely still. The moment I touched him, the thundering reality hit me. He was cold, and deadly stiff.

Do you know, you don’t even scream straight away? You just try to take in a truth that’s so terrible, your senses reel and reject, and you freeze.

Then I snapped into real time and ran to the window to call for help.

I could see my then husband, Mike, below, pacing out the lawn for a marquee for Oliver’s birthday party, lots of little four-year-olds coming to eat cake.

I yelled then - louder than I’d ever screamed anything in all my life - and pulled at the safety bars of the window. One bar came clean away in my hand. I rapped furiously on the window pane and I saw Mike look up, his face at first curious, changing within a split second to horror. I saw him start to run. I turned back to the cot.

The strange thing is, I’d never seen a dead person before. But I knew death - I’d seen dead pets, long ago, in my childhood. I recognised the hopeless, despairing numbing certainty of rigor mortis in my  darling boy. My precious, warm, milky son was now a stiff cold statue, like a porcelain doll.

The cold of his body was chilling - the back of his head, where I always put a steadying hand, felt like a ball of stone. His face seemed cruelly squashed and his flesh deadly white, except for purple blotches where the blood had settled.

I staggered back into the rocking chair, where the previous night, just a few hours before, I’d given him his evening feed, and I rocked this little statue while Mike bounded up the stairs, took in the horror, dialled 999, instructed our wonderful nanny, Alex, to look after Oliver and James, and we waited in shocked silence for something to happen.

It was hurting to hold him, he was so cold, but I couldn’t bear to let go.

A young policeman almost fell through the door, white with shock.

He knelt beside me and I could see his eyes were reddening. Then a tear whitened his cheek.  

‘I’m so terribly sorry,’ he faltered. ‘You see, the same thing happened to me . . .’

'It's lovely to have a baby in the family again': After the death of Sebastian, Anne went on to have another son

I held out a hand to him. Mike stood back, almost unable to take in the monstrosity of it all, and then he put an arm around the policeman’s shoulders. We all surrendered to more tears.

And so there we were, like actors in some grotesque, slow-motion dream sequence from a morbid movie. Three grown adults weeping like babies over a dead child, in a pastel playroom nursery on a sunny summer morning in London.

When I look back on it now, it’s almost gothic in its melodrama. And yet there it is. It really happened. To tell its awful truth, even after 20 years, is not to dwell on grief but to find a way to cope with life. 

Anyone who’s ever been through anything this tragic knows that real life can appear so unrealistic no film director would accept the storyline. I often think of Madeleine McCann’s parents. The horror they’ve been through would have to be watered down to become believable. It was the same with us.

My little family fled to my parents’ home in Bournemouth to get away from the paparazzi. My dad stood watch at the garden gate with a high-powered garden hose to fend off the long lenses. We even laughed about it at the time. Yet it worked — it kept the photographers away.

I asked if we could donate Sebastian’s organs to children who needed, perhaps, his corneas, his heart, his kidneys. Right away, I was desperate that his death should mean something. We were told it wasn’t possible, since he’d been dead for hours and there would have to be a post-mortem.

Lighting fires: After the death of Sebastian, Anne and Mike kick-started a cot death awareness campaign

Sky News burbled in the corner of every room. ‘Anne Diamond’s baby has died of cot death,’ the presenter said and I thought — how come they know what’s killed him when I don’t?

So intense was the present that the future seemed impossible to comprehend.

But life started to go on, even though every minute felt like a betrayal. I decided I wanted a chorister to sing at Sebastian’s funeral service, and my best friend Shirley, who’s a whizz at fixing just about anything, managed to find a boy living nearby who was the runner-up to Chorister Of The Year.

She got him to turn up and sing a beautiful Nunc Dimittis, and he even brought a fellow trumpeter with him.

Wonderful, sad, inspirational letters flooded in from the famous and sympathetic and similarly bereaved. The former England footballer Jimmy Greaves had been through the same tragedy himself and wrote to offer his sympathy.

One card was from a woman in Andover, who had lost her child to cot death, too. She wrote: ‘They do say time heals but believe me, Anne, you never forget. My Robert would have been 50 now. I always have a little weep when I go to his grave. I am nearly 77 years old.’

I remember reading that and thinking — will I be able to go on and one day look back over so many, many years at Sebastian’s short life and death? Will I still feel such pain, for ever?

Sweet dreams: The number of cot deaths has reduced dramatically in the last 20 years. Research shows that the risk is cut if babies sleep on their backs

And now, 20 years later, here I am. Lucky, very lucky, in some ways because my baby’s death did indeed spark a life-saving campaign. So many others I have met lost their children when research was in its infancy, and there were no campaigns to start, no advice to give.

But in 1991 we had indeed found a breakthrough and yet the information had not been passed on to mums and dads in Britain.

They’d found in a huge national study in New Zealand, and in a smaller study in Avon in the UK, that the babies who were dying of cot death were those who were lying on their tummies to sleep. The truth is that the Department of Health knew this astonishing fact and was waiting for more data.

In fact, they’d agreed to let British babies act as a ‘control group’ for the intervention in New Zealand, where every mum and dad was being told to turn their baby over.

It’s a scandal that’s almost impossible to fully grasp. Our Department of Health had actually agreed NOT to tell parents the life-saving advice, while in New Zealand (and in Avon) there were full-blown campaigns to save lives.

That’s the point at which Sebastian was born, lived his short life, and died. I still believe that if we had lived in Bristol or New Zealand, he would be alive today.

In my anguish, I turned to everyone I could think of to get British parents the same deal.

I even went to Jeffrey Archer, to ask how I could get to see the then prime minister, John Major. He advised me that ministers are like firemen. They don’t have time to put out every fire, only the hottest ones.

So I decided to make a big blaze.  That’s why I prostituted my grief on every TV and radio programme I could, at this very time 20 years ago, to demand a life-saving campaign out of the Government. And it worked. I got a call from Virginia Bottomley, then health minister. Would I pop round to her offices in Whitehall?

I had trouble convincing her we needed a TV campaign. She told me that young mothers didn’t watch TV, they read baby magazines. I was gobsmacked. Who did she think watched Richard And Judy, Neighbours, Home And Away, and my own programme, Good Morning Britain?

I had a mailbag from young mothers who liked to breastfeed while they watched me, and thanked me for the little clock in the corner of the screen - it helped them time ‘ten minutes each breast’!

I made my own TV ad, and with money from Mothercare we showed it in the Coronation Street ad break. We could only afford one showing, but it worked. The next phone call from Whitehall showed the Government had woken up.

And that is how we eventually got the Back To Sleep campaign.

It ran on TV throughout the winter of 1991 and started saving lives immediately.

Cot death numbers plummeted from 2,500 a year to about 300, where they stubbornly remain even now. The Golden Rules still apply - babies must sleep on their backs, must not be overwrapped, and smoking near them can be deadly.

If only we could get young parents to stop smoking, the figures could fall further. But it’s hard to get that message through to a hard core of desperately poor, often single mums who can’t cope as it is.

Even more frightening is the evidence that some young mums are beginning to talk on internet chat rooms about the fact that laying your baby on his tummy might actually make him sleep longer, and more soundly.

After 20 years, they seem to have forgotten the spectre of cot death and could be putting their babies in danger, despite the warnings they’re given in hospital.

Perhaps it is time for another cot death campaign, to renew the life-saving message. Don’t let’s wait for another high-profile death to spur us into action.

Sebastian has no grave at which to weep. Only his father and I know where his ashes are scattered. That’s how we wanted it. I prefer memories and photographs to remember him by.

One well-wisher wrote to me: ‘If heaven is like some sort of fantastic Disneyland, then think that Sebastian is already on the rides!’ When his death was young, that was a comfort while I needed such emotional props.

Today, though, I think of him as the young man only his mother still knows . .