I'VE written this column before. Each time the catalyst has changed. But I've written this column before.

Here it is: Men - step up. Not please, not can you, not it would be great if you could. Now. Step up now.

Last Wednesday, Sarah Everard left her friend's house to walk home through south London. Not that late at night, just 9pm. Wearing bright clothes, sticking to brightly lit roads. Phoned her boyfriend to let him know where she was.

And then, despite every mitigation, Sarah went missing. In response, men were not warned about their behaviour. Men did not subject themselves to self-enforced curfews in case one of their number might cause harm.

Men did not turn to the crowd comfort of social media to confess to each other about their regrets at displaying misogynistic behaviour and promise change. Men did not begin to organise vigils or marches to tackle violent behaviour.

A number did tweet to ask how they might support women as they move about in public. I will not say thank you. It is a bare minimum and it is long overdue.

Instead, familiar turntables played familiar songs. Women's behaviour was questioned and condemned: Why would women go out alone at night? Why would women wear headphones? Why would women put themselves at risk?

READ MORE: Improving inclusivity is placed at the feet of women - men step up

Baroness Jones, a Green Party peer, did suggest a blanket 6pm curfew for men but you might imagine how that went down.

Since Sarah vanished last week, six women and a girl have been reported as being killed by men. In the UK, on average, a woman is killed by a man every three days.

The majority of these killings go unremarked upon but, every so often, one woman's absence becomes an enormous presence and a public conversation begins.

This time the conversation has focused on women's fear, the low-lying, commonplace disquiet of being a female out in the world.

Every woman knows the rules: don't go out alone at night. Keep your keys in your hand, hold your bag close to you, phone a friend, don't make eye contact, don't speak back, be polite and pliant.

Why didn't Sarah take a taxi, social media asked. Women replied in their hundreds with stories of being molested or threatened in taxis. They talked of giving fake names and addresses on taxi apps.

There is no such thing as too much when you are a woman trying to stay safe.

During the pandemic, outdoor exercise is one of the few pleasures we have. Over the past few months, there have been umpteen stories about how women fear running alone because of the heckling they receive. They modify their routes or they miss out altogether because there simply isn't time during daylight hours.

Daylight hours, though, still aren't safe from male heckling, cat calling, abuse. The conversation normally focuses on what women might do to avoid having their enjoyment spoiled rather than asking men what they plan to do to stop their peers behaving in such a way.

On Wednesday a new survey from UN Women UK showed that 97% of young women aged 18 to 24 had been subjected to sexual harassment. The surprise is that it wasn't 100%.

I walk home routinely through the city at night. I have walked through Bangkok and Dublin on my own; strolled through Ho Chi Min city and Havana on my own. I have travelled by rail and sea and air alone; stayed in hostels and hotels.

And all the while a sense of tempting fate. It is only by some blind luck, a blessing from Fortuna, that I made it around the world and back. Do young men survey their travels and end with a sense of relief. Do they hell.

They don't understand their good fortune in not having to carry with them the many additional burdens women carry.

Males and females experience the world differently. They are conditioned from a young age to disparate behaviours in public - men take up more space, they are comfortable being loud, they don't second guess where they are and what they are doing.

At a low level, they objectify women, they invade women's spaces, they impose themselves on women. That behaviour slides up a scale from irritating to intimidating to distressing to fatal.

And women are told, again and again, they are responsible for how men act.

In 2011, I wrote about the Slutwalks, a global movement in response to a Canadian police officer telling Toronto University students, "I'm not supposed to say this," but to prevent sexual assault, "avoid dressing like sluts."

"We must shift the paradigm of rape blame away from victim to perpetrator," I wrote. It was obvious - a call made by feminists for decades. "Not all men," was the response - not all men are sexist, rapists, murderers, fill in your own blank. No one had said they are. Imagine all the energy used in taking offence was channelled into making change.

In 2014 I wrote about the These Streets Were Made For Walking march through the South Side of Glasgow following a spate of attacks on women. I wrote of how I love walking at night and how I felt ownership of the streets but how every successful walk felt like a bullet dodged. "Who tells their sons to make sure to walk on the opposite pavement to a women, walk in front and not behind them?," I wrote.

"Or to try not to startle any lone females they see scurrying, cowed, in the evening. To mind their personal space. Who tells their sons to be watchful of other men: the punks, the cat-callers, the bottom-grabbers?" Not all men! A male friend took such umbrage at the idea he should cross the street so as not to appear threatening, he stopped speaking to me.

In 2019 I said men must modify their behaviour to take account of female discomfort at sharing toilets as unisex facilities become more commonplace. "Not all men," was the response, with the new added charge of bigotry.

It's 44 years since the first UK Reclaim The Night March. Here we are, still. Tomorrow there will be Reclaim The Night vigils across the country in response to Sarah Everard's death.

We're all repeating ourselves now and we're exhausted by it.

Here, again: Not all men are sexist or sleazy or violent but violence against women is overwhelmingly perpetrated by men - men are the problem and they must be the solution.

Fathers, teach your sons. Friends, call out your mates. Colleagues, do not stand by.

There has to be a turning point, there has to be a time of change. Now, make it now.