ALEXANDRA SHULMAN'S NOTEBOOK: I learned my stepchildren's real story

This weekend my grown-up stepchildren Emma and Matthew are staying. 

They have come for the launch of their half-sister Helen Longstreth's book Things In Every Room.

I absolutely love my stepchildren but they had a tough childhood, as anyone who reads this moving and harrowing memoir will discover.

The book tells the story of Helen's alcoholic father, Frank, and the damage he inflicted on his family, but also the love she and he had for each other. It's a highly evocative portrait of the complexities of familial relationships and growing up.

Emma was 12 when she moved in with us – her father being my then husband Paul Spike. This is described in the book as: 'Emma left to live with her father and his new family in north London.'

Though factually accurate, that is not how I remember it.

I had just given birth to my son, so almost overnight I became a first-time mother and a carer for a pre-teen girl who'd been transplanted from her home, school and friends in Bath to start a new life in London.

I saw her move not as an insouciant choice but an emergency measure – Emma had to be rescued from her stepfather Frank, who was frequently abusive to her and her older brother Matthew.

Reading the book is a curious experience. As a stepmother you become involved in a whole other family, and yet you only see half of what goes on. There is another world that you are aware of – which may hugely influence your own – but the events are being acted out on a stage somewhere else. 

Your stepchildren, meanwhile, are players on both stages, literally stepping between the two.

Emma and Matthew's mother, the writer and translator Maureen Freely, had an acrimonious split from my husband and there was bad blood between them before I came on the scene. 

Maureen went on to have Helen and another daughter, Pandora, with Frank and, as the years passed, I only learned about what was happening in her household from Paul, who himself only had a partial view.

Reading Helen's book, I finally gained a greater insight into the other half of the story and learned things about Emma's family I'd never realised.

It is a tribute to all that we have gathered this weekend – my son and ex-husband included – to give Helen's remarkable book a good send-off.

Why we must fight scourge of knives

The spring sunshine has been sullied with the news of 21-year-old Finbar Sullivan's fatal stabbing on Primrose Hill, London. I have sat there, enjoying the sun and watching young people like Finbar having fun in what was previously a safe place.

It's another example of how knife crime is rampant in the capital and needs to be stopped. 

Restarting the many youth centres that have been closed over recent decades would be a good place to start.

They gave disadvantaged young people the chance to be together, to hang out and play sports alongside trained counsellors. 

Now there's nowhere in our crowded urban city for them to go and violence proliferates. The result is that innocent victims like Finbar lose their lives, even in the gentrified areas of Primrose Hill.

Better the Devil you know, Anna...

When The Devil Wears Prada was first published in 2003, Vogue editor Anna Wintour brushed it off like an inconvenient flea.

Her oft-repeated line was that the nightmarish boss at the centre of the book – written by one of her former assistants – was obviously fiction.

Eventually the book became a hit film and, an expert at reading the runes, Wintour began to lean in to the narrative, turning up at promotional events wearing Prada.

Last week she went one step further, posing for the May cover of US Vogue alongside actress Meryl Streep who plays Miranda Priestly, Wintour's fictional counterpart.

Far from keeping the magazine distanced from the film, the shoot suggests Wintour knows that the balance of influence has shifted.

Vogue is no longer able to survive as purely a magazine but has had to shift into the entertainment business. 

Anna now needs to associate with the brand of The Devil Wears Prada just as much – possibly more than – the Devil needs to hold hands with her.

Stylish alchemy of the changing Chanel

The other day I took a navy boucle Chanel jacket out of my wardrobe to wear to a funeral. For years the structured shape and tight sleeves of the trademark Chanel garment have felt a little frumpy, but now it's all change.

Chanel has undergone a total revitalisation under the new creative director Matthieu Blazy, who in one year has turned what was in danger of becoming a moribund fashion house into the name of the moment. 

The alchemy is impossible to pin down, but his shows have been joyful and inclusive (one even held on the New York subway) and the clothes, while fabulously expensive and clearly Chanel, are wearable.

During Paris fashion week last month, the Chanel store was mobbed by fashion editors actually spending their own money on the new collection – something they seldom do. 

Look out for Chanel copies – particularly of its fringed striped jackets – on the High Street this summer.

Chasing youth cost Angels their beauty

When I saw the pictures of the three Charlie's Angels reunited to promote the 50th anniversary of the show, I was horrified. 

Presumably the amount of fillers, surgery and other interventions that these women – Kate Jackson, 77, Jaclyn Smith, 80, and Cheryl Ladd, 74 – have inflicted on themselves is to ensure they remain relevant in age-obsessed Hollywood. 

But rather than make them look younger, they have wiped clean any trace of the good looks they were blessed with and replaced them with a dystopian vision of old age. Why would anyone do it?