ON his way to a job interview at the Scotsman newspaper, Andrew Marr boarded the sleeper from London to Edinburgh. It’s a story he has often told, and gets richer with every telling. Reaching his cabin, he discovered his companion for the night was a chain-smoking individual in a semmit, who took one look at him and growled (I paraphrase), “You’re not one of those poofs who dinnae drink?” To prove his macho credentials, Marr spent the next seven hours swigging beer, fag in hand. He disembarked and headed for the editor’s office reeking like a brewery and kippered by smoke.

One of the perils of the cross-border sleeper was not knowing who your room-mate would be. I’ve never taken that trip, knowing I wouldn’t sleep. Not even the romance of it – described by Norman MacCaig as “being carried sideways through the night” – could overcome my distaste for arriving in London, red-eyed and wabbit.

The thought of a stranger sharing my cabin was not what put me off. Now, however, the fabled Caledonian sleeper has been a cause of panic for those who fear that predatory men could book a place in a woman-only cabin by claiming to identify as female. Rupert Soames, the chief executive of Serco, which runs the service, dismissed these concerns out of hand, claiming that the Caledonian’s travellers “were not deceitful”. Naturally, this only stoked the flames. He did point out that there is a call button in every compartment, but presumably some will not deem that sufficient protection.

The issue of onboard safety follows various reports of unease over the prospect of transgender women, who are still anatomically male, gaining access to women’s changing rooms or toilets, or other single-sex zones. Nor need they be predatory to cause consternation. One adventurous pair of female protesters claimed they identified as male and, despite their appearance, were allowed into a men-only swimming pool (where one of them swam topless). Their exploit was intended to highlight the ease with which such trespass could happen, and reflected public terror of embarrassing or upsetting strangers. Generally, we trust what people tell us, even if the evidence points to a lie.

Now, of course I would not like to discover that the stranger with whom I was sharing a cabin was male and malevolent. But some perspective is needed on this steady trickle of alarmist tales. So far, the situations posited are hypothetical. Thus while women fret over encroachment on their privacy and safety, and torment themselves with scenarios in which they might come to harm, trans men and trans women are daily dealing with mockery, harassment, intimidation, and worse. Germaine Greer is entitled to think that trans women are “not women”, but it is only an opinion. If someone has altered their anatomy, their gender is also changed. If they still carry a physical echo of their former self, is that so different from those women down the centuries who have appeared masculine in appearance or dress, or men who have had an effeminate demeanour? Now that surgical transformation is possible, who would go through that gruelling procedure without genuinely identifying with the gender they are joining?

While you can understand those who feel unsettled by the speed with which gender change has become commonplace, there is little reason to be scared or hysterical. By contrast, transgender men and women, transvestites, and those who identify themselves as the opposite sex – or no gender at all – are dealing with real and immediate threats. They have much greater cause to worry than the rest of us.

So surely the Caledonian sleeper crisis raises the issue, not of how to police ourselves against a thug taking advantage of a politically correct culture, but of the nature of gender. What does it mean to be male, female or intersex? One man’s version of masculinity can be very different from that of his neighbour, despite sharing an identical physique. The same goes for women. Or those who find themselves floating between the two in an area hitherto barely acknowledged, though it must be as old as time itself.

After all, in what is femininity or masculinity rooted? Other than the physical mechanics that allow us to procreate in the traditional way, it is what goes on in our heads that determines who we are, and how we want to be seen. There are countless men now who dress as women, yet will never allow a surgeon near them. So what? For them, the outward declaration is enough.

One of the most heartening aspects of a civilised society is embracing all shades of difference. Life would be numbingly dull if all distinction between genders was sand-papered, but the unchallenged chasm that once yawned between male and female is gradually, mercifully being bridged. Slowly we are recognising that fundamentally there is no huge distinction between any of us, no reason to think of anyone as “other”. Scaremongering about rapists disguised in trans women’s clothing might set the process back a little, but so far as I can tell our journey to enlightenment remains firmly on track.