Yesterday, an 82-year-old woman called Palmira Silva was killed in her garden in Edmonton, north London.

She is the hundredth woman killed by a man this year; the first was 87-year-old Elsie Mowbray, who died in hospital on 8 January from injuries sustained when her house was burgled on New Year's Day. A 33-year-old man has been charged. The 50th, according to the list maintained by campaigner Karen Ingala Smith, was Ann Maguire - the teacher stabbed in her classroom.

I was shocked when I read of Palmira Silva's death - not by the fact of it, unfortunately, but because of the way in which it happened. She was beheaded.

The assailant is alleged to be a 25-year-old man, who "waved a machete-like weapon as he wandered screaming and shouting through private gardens", according to the Guardian.

Let's take a moment to talk about connections.

The Sun's front page this morning reports that the alleged perpetrator was a "Muslim convert". Inside, its report reads:

"The killing follows the brutal beheadings on video of two US journalists by IS jihadists. But police yesterday stressed there was no evidence of a terrorist connection."

Oddly enough, like the Sun, my thoughts immediately went to the IS beheadings when I heard about this story, too - albeit for totally different reasons. On Tuesday, I wrote a piece on how revenge porn, hacked photos and online harassment were, in my opinion, forms of "terrorism". They are not intended merely to harm the individuals targeted, but to create a spectacle which makes all women feel a little more insecure, a little more afraid.

The reaction was, shall we say, mixed. Among the critical comments, one theme repeatedly came up: I was "hysterical" to compare "real terrorism" with having naked photos published on the internet. Many a wag tweeted me to the effect that they would rather get online abuse than their head chopped off in Iraq.

Because I am nothing if not willing to pour hours into pointless arguments, I replied to some of these men (#notallmen) that of course, the comparison wasn't perfect and true in every way - it would not then be a comparison. They would just be literally the same thing. But I still think the similarities of intent, method and effect are noteworthy.

And then a woman had her head chopped off, not ten miles from where I live and work.

Now, I have no idea whether Palmira Silva was targeted because she was a woman. We might never know this. She might have tried to be compassionate to the killer, she might have known him a little, she might have simply been the first person in his way.

But here is the second shocking fact about the way she died: Palmira Silva is the third woman to be beheaded in London this year.

On 3 June, a 38-year-old woman called Tahira Ahmed was found decapitated at her home in West London. The neighbours reported hearing a loud argument. Her husband has been charged with her murder.

In April, 60-year-old woman called Judith Nibbs was beheaded in Shoreditch. Her 67-year-old estranged husband was found at the scene. Police are not looking for anyone else. The day after Judith died, her daughter - who is severely disabled - tweeted the single word: "Mum?"

In the last few years, Karen Ingala Smith - the CEO of the charity which I chair, Nia - has maintained a list of every woman killed by a man in this country. Yesterday, she wrote about beheadings. As well as Judith Nibbs and Tahira Ahmed, she has recorded others:

Last year, in June, Reema Ramzan, 18, was decapitated by boyfriend, Aras Hussain, 21. The year before, in October 2012, Catherine Gowing, 39, was decapitated and raped by serial rapist Clive Sharp, 47. In March the same year Elizabeth Coriat, 76, was decapitated by her son Daniel Coriat, 43; earlier the same month, Gemma McCluskie, 29, had been decapitated by her brother Tony McCluskie, 36.

In May, she wrote about Ann Maguire, the 50th woman to die this year. It was not an "isolated incident", she argued: "Between April 2001 and March 2012 . . . 31.8 per cent of homicide victims were women, 68.2 per cent were men. 6.1 per cent of people convicted of murder were women, 93.9 per cent were men". In other words, men kill men, men kill women - but women only rarely kill anyone at all.

I remember the response to Karen's piece: many people were angry with her at talking about male violence in this context. Some accused her of "politicising a tragedy" or "scoring points".

If you want to talk about politicising a tragedy, let's talk about the death of Palmira Silva. Why did her death make the front pages, when Judith Nibbs and Tahira Ahmed did not?

Because she was not allegedly killed by an ex-partner or family member, which is "normal".

Because her death seems to be random - it could have happened to anyone, even a man.

Because terrorism is real when it's Islamists against the west, but violence against women is just the background hum of our lives.

This year, in the city where I live, in twenty-first century Britain with its smartphones and coalition government and internet commenters telling me that feminism has gone too far, three women have been beheaded.