I WORE ‘Whiteface’, my cousin Noreen wore ‘Brownface’ and we casually walked around the estate we lived on in the roasting summer of 1977. Dressed in a grey business suit and leather brogues, and Noreen in a shocking pink and neon yellow, silk headscarf and polyester housecoat, we felt oh-so-11-year-old creative and clever, completely misinterpreting peoples’ incredulous staring, for admiration at this striking-looking couple.

The attention to detail was eye-watering: I had attached a Rice Krispie to my face with eyelash glue, covered it with white greasepaint, inserted a single hair that had been stretched with the edge of a pair of scissors so it curled in that way that wart hairs do. Noreen had blacked out her front tooth with liquid eyeliner that tasted like ink. The greasepaint had been purchased from a theatrical supplies shop. I’d bought ‘white’, which in reality was a sort of light powder grey, and ‘brown’ which was a luminous orangey, American tan tights sort of colour. I can’t quite remember the thought process that ended up with mixed-race, white-skinned Noreen deciding to go for the brown face, and brown-skinned me opting for the white face, but I’m fairly sure it was to maximise our creativity, rather than to make any specific comment about race.

We played with our skin colour in the same way we played with our hair – short or long, our clothes – business suit or housecoat, and our warts – with hair poking out, or not. These were innocent times when averting boredom was the main objective in life and our parents were just relieved to see us busy – so just rolled their eyes when we arrived home with greasepaint melted into our clothes after a long, hot day of traipsing round the estate chatting to random strangers, rather than talking to us about our choices of greasepaint colour.

But what if there was more to it? What if my choosing the white greasepaint was because living on a predominantly white estate, attending a predominantly white school, casually getting called the P word, I subconsciously wanted to be the same as everyone else? What if Noreen picked the brown greasepaint because she wanted to poke fun at Indian or Pakistani people, because she resented that part of her heritage, or she was, in some way, ashamed of it? I genuinely don’t know the truth about that. However, reading about Canadian Prime Minister Justin Trudeau last week when pictures emerged of him wearing “Blackface” and “Brownface” 20 or so years ago, made me really think about that summer of 1977, which I had firmly stored under “Bat-shit crazy things I did as a kid”, alongside putting a whoopee cushion under a visiting relative’s mattress and secretly recording their reaction to it going off. For me, if the Trudeau incident does anything, it should get us all examining our behaviours in the past – before we learnt ‘stuff’, before we met and worked with people from different backgrounds, from different faiths and heritages, and before we stopped seeing our entire world as consisting of the estate we lived on.

And it seems others have been considering this issue in the last few days too. The comment I’ve heard most is – how can dressing up as someone be offensive? Strictly speaking it’s not – if you dress up as Shrek you’re going to be digging out the garish green face paint and it’s all going to be fine, Homer Simpson and it’s sunshine yellow. But if you’re blacking up you’re also applying centuries of history with every careful stroke of your face paint. You’re reminding your audience, and, it could be argued, celebrating an age when white entertainers routinely wore ‘Blackface’ to ridicule and shamelessly mock black people as a form of entertainment, at a time when black entertainers were rarely, if ever, given the stage. You’re reminding us of that troubling period of Scotland’s story when black people were so dehumanised it was considered “good business” to scrub them until they almost bled to get the highest price at auction. You’re encouraging a false stereotype of what black people look like: With every uniform smear of black face paint, you’re ignoring the incredible diversity and beauty of the shades of black and brown skin, reducing millions of people to a uniform group – minimising the history of black and brown-skinned peoples in the last couple of centuries: the subjugation by empires, the inhumanity of slavery and the cruelty of racism.

A dear Jewish friend said to me at the weekend that he couldn’t see what the fuss was about. I responded that blacking up was based on a depiction of black people that was stereotypical and sought to mock and belittle. He seemed unconvinced. I asked him what he thought of the stereotypical depiction of Jewish people in 1930s' Europe. Immediately a flicker of pain crossed his face, followed by a long moment recognition. “But those depictions…weren’t true,” he said. Exactly.

It’s no surprise that many don’t see what the fuss is about. If people don’t know the history how on earth are they supposed to put the two things together – the seemingly innocent, creative act of dressing up with the pain of hundreds of years of history? In our schools the slave trade, when and if taught, is seen as an English issue, not something that Scots encouraged and benefitted from as well, and the Civil Rights movement is taught as something that affected America only. And the worst complaint of all – that was then, this is now. To that I say that even I have not been immune to wishing we could stop looking back at history and look forwards, but that approach only works if we all – every single one of us – know, accept, understand and learn from our history. Only then will we understand why blacking up is utterly disrespectful, demeaning and racist. And for those beleaguered-looking folks who’ve said to me, “I just don’t know what I can say and what I can’t any more”, I suggest using Mr Trudeau’s predicament as a way of having that conversation with people of colour who are acquaintances, friends or colleagues. Use it to think about decisions you’ve made in the past – only you know if you made them in a race-aware way, or whether race did not enter your thought process. Don’t beat yourself up, just be relentlessly curious about yourself. So that when your 11-year old asks if he can go black-faced around the neighbourhood at Halloween, you can let him express his creativity, but you can also have that real, informed confident conversation about why it’s maybe worth thinking again.

Uzma Mir presents The Thing About Race on BBC Radio Scotland today at 1.30pm.