Janet Street-Porter: When I was stalked, I got help. Where were the police for Arsema?

A young girl lay bleeding to death in the lift of her block of flats in Waterloo, south London. She had been stabbed at least 10 times. At that exact moment, I was only two hundred yards away, filming interviews with the public in the street around the corner. How could I have known? As we swatted away the odd persistent drunk (there is a refuge nearby), I chatted to passers-by under a grey and dismal sky, with no idea of the tragedy unfolding nearby.

I've thought about the horrible end of 15-year-old Arsema Dawit's life a lot since then. This blameless young woman lies in a mortuary because of the obscene obsession of another person. She didn't do anything wrong other than try her best to ignore him and live as normally as possible, always aware that she was being watched. She received frightening texts on her mobile indicating that he was becoming increasingly jealous at being rejected, but who could have foreseen this?

Four days after her body was found, a 21-year-old student was charged with her murder. Now an investigation has been started into why nothing happened after Arsema's family reported the threats to the police. Having left her native Eritrea, this young girl was, by all accounts, working hard at school and was very good at maths. At the weekends she sang in a church choir, which is where her stalker spotted her.

This isn't a crime that's got anything to do with youths and gangs – it's a classic case of stalking that got out of control. Some writers have made the mistake of assuming that stalking affects women more than men, but it's not true. A stalker is suffering from a mental illness – they can't understand why the person they are fixated on is not interested in them. In pursuing their love object, they end up making that person's life completely intolerable, but they couldn't care less.

Stalkers are unpleasantly self-centred and potentially dangerous people, but sadly, the police often adopt the attitude that somehow, if the person being stalked is a woman, she might have encouraged a bloke and then got tired of him, and that it's the women's fault that he's hanging around. Of course, if you're famous, somehow it goes with the territory.

I know from my own experience how horrible it can be. Once a woman telephoned me at home and threatened to turn up and kill me because she thought I was having an affair with her husband. When I said I had no idea who he was, she shouted: "I knew you'd say that." Then she hung up. The police stayed with me for hours in case she appeared. Luckily she didn't.

Another time a man who'd sent me loads of letters rang and told me he was going to commit suicide if I didn't meet him at a mainline station. I'm afraid to say I told him to get on with it. I've had blokes following me in the street and once I broke the fingers of a man who pursued me around a supermarket by smashing a large can of beans down on his hand as he shoved his crotch against me. I left him screaming in pain. I've had one nutter who posted a page torn from a Bible through my letterbox and slept rough in the little park outside my house so he could watch me.

But the most persistent stalkers I know have made the lives of two male friends completely miserable. Former veterinary nurse Sarah Bartholomew is locked up and awaiting sentencing after admitting pestering David Walliams since 2004 – four years of unwanted filthy letters, emails, gifts of her underwear, texts. She stationed herself outside his house and photographed him in it, completely invading his privacy. She sent so much stuff that the prosecution case was 1,000 pages long.

Another male friend had the same German woman standing at the end of his street monitoring his movements for four years. She would tie a balloon to his front railings and post letters though his letterbox every day. Even though he is gay, she was undeterred, even after his cleaner chucked a bucket of water over her.

Knowing what it's like, having experienced only low-level stalking, I know that poor Arsema must have been through hell. She was badly let down by the police, and no matter how much handwringing and apologising they might do, they can't give her back to her mother.

YSL's send-off was a fashion free-for-all

Without a doubt, Yves Saint Laurent was the greatest fashion designer of the 20th century – and his funeral last week was an opportunity for his glamorous friends to dress up to the nines. A smart black trouser-suited Carla Bruni was joined by Claudia Schiffer in a gorgeous ruffled blouse. Some mourners' choice of headgear was a bit whacky – Vivienne Westwood wore a knitted beanie hat and John Galliano donned a pearly king's beret, but hey, that's fashion people for you. I met Yves Saint Laurent when he opened his first Rive Gauche boutique in London. Cheekily I wore a coat by Zandra Rhodes, and the famously shy designer told me how much he loved her stuff. His sand-coloured safari jackets and black evening trouser suits are still classics today. I commissioned a documentary about him for the BBC, but by then Yves was a bit troubled, spending half an hour in front of a mirror spraying his hair until it resembled Mrs T's helmet coiffure.

Cherie - too posh to wash (up)

Cherie Blair tells an interviewer that the Queen does the dishes after a family barbecue, just like a normal human being! This remark tells us more about Cherie than the Queen, who is obviously an experienced hostess.

I wonder how many times Cherie did the dishes during her freebies at Silvio Berlusconi's lavish palazzo in Sardinia or at Alain Perrin's 15th-century chateau in south-west France?

Funny how Tony and Cherie have seamlessly segued into a life of grand houses in town and country.

Something tells me that she'll need a bit of help understanding how to deal with the staff.

Essence of chip fat is not a Chelsea aroma

At the Royal Academy last week, a small ginger man in a garish white suit was escorted around the party by a tall blonde beauty. He was, I discovered, trendy chef Tom Aikens (right). But why wasn't he up to his elbows in chip fat at his cordon bleu fish and chip eatery in Chelsea, where residents are complaining vociferously about the smells emanating from his kitchen? Posh people don't like paying £2mfor a tiny flat off the Kings Road, only to discover the first thing they smell when they get home isn't the jasmine in the garden but the unmistakeably common pong of chips.