25/02/2015 05:03 GMT | Updated 25/04/2015 06:59 BST

Incidents Like the Paris Metro Are Shocking, but Casual Racism Is Alive and Kicking

A disturbing video on the news last week showed English football fans on the Metro in Paris pushing a black man off as he tries to board. Twice, this happens, as they chant 'We're racist, we're racist and that's the way we like it'. Yes, it is 2015, before you have to check. This is vile and embarrassing, and sad for other football fans who would not dream of this sort of behaviour, but may nevertheless be tarnished with the same brush.

You can't ever assume a 'type' of person will be racist. People often say offensive things without really thinking about it - it's the not really thinking about it that's the problem. I've become infuriated with comments I've heard from friends, colleagues and acquaintances who would never consider themselves racist. I don't think they are either, but they're not thinking very hard about what they're saying.

I find it pretty shocking to be having everyday conversations with people I know and like, who are reasonable, nice people, only for them to drop a bomb like "you'll feel safe with your big black boyfriend", when discussing travelling in Thailand. The implication being that not only his size but also his skin colour might ward off potential muggers. Black men are threatening, not to be messed with. That is what you are saying.

The reason I feel safe with my boyfriend is because he's a 6ft2 personal trainer who'd calmly talk us out of any dangerous situation if he could, and it's pretty obvious that two people might be less easy to attack than one regardless of their gender. I appreciate the use of 'black' as a descriptive term in some circumstances, for example if you were trying to point out my boyfriend in a room full of Chinese people. I don't appreciate it when used in the context of explaining why people might be more afraid of him than someone who was just big. And no one has ever referred to my former white boyfriends as 'your big white boyfriend' or, more appropriately for anyone who met him, 'your loser white boyfriend'.

I've heard "I don't go that dark" when discussing a good-looking actor, as if you can pick and choose who you fall in love with, as if men are an accessory, a commodity, because skin that dark just wouldn't match your handbag. When these things happen I swing between being angry and vocal, and brushing it off because I know they don't mean it. Sometimes you're just shocked by what you've heard and miss the chance to say something because you're too busy trying to figure out how someone you actually know could say something like that about a person.

In my job I've had contributors and even a presenter saying things that I find offensive and found myself just sucking it up for fear of losing a story or person you need for a programme. It's uncomfortable to write that. We've seen what happens when people are afraid to say something for fear of 'upsetting the talent'. Some things just shouldn't be let go. Casual racism is one of them.

Other comments I've heard... where to begin? Someone asking why my boyfriend would be interested in going to visit the Isle of Wight, because why would black people be interested in the countryside? This 'joke', half pathetic word play on the 'Wight', half bizarre assumption that black people - that big homogeneous group of them - aren't interested in cultural trips, has stuck with me. Too busy listening to rap and buying trainers, are black men!

How well-endowed my boyfriend might be, another common topic of conversation you'd think was really too old and weird to still being bandied about. Why is his body up for public discussion? Apart from being a boring stereotype that adds no value to anything, I just wouldn't dream of asking a fully-grown woman about the size of her partner's genitals, or even mentioning it. Aren't we past this? Apparently not.

And finally, of course, to Twitter, the bastion of reasoned opinion and public debate. Where someone recently commented, when I pointed out that BBC2's Inside the Commons featured almost entirely white people, that 'the diverse' should assess their work ethic. Charming. At least you can ignore those people. It's harder when someone you like or respect says something you don't think should be said or joked about.

These things bother me, but I don't contend with both the overtly racist people in society, shouting at you on trams and pushing you off trains as well as these subtle, everyday occurrences from people you may know and like. The people you hear saying these things and making these assumptions can be smart, tolerant, friendly, fun, interesting. They've grown up in multicultural Britain. The fact that it just generally happens like this is just as concerning as those overtly racist people pushing a black man off the metro. It's these subtle comments, the assumptions steeped in stereotypes, that remind you we haven't quite reached where we need to be just yet.