As I got very wet cycling round and round the Emirates Stadium this morning, I was pondering whether a man could have got away with calling Danny Alexander a ‘ginger rodent.’

Maybe – that was the conclusion I came to. Then I got pondering whether a woman other than Harriet Harman might have been able to deliver this jibe without provoking such an outcry. I don’t know, I thought as the rain started to freeze my neck, but again, just maybe.

There was definitely something about it being Harriet, she of the Equalities Bill, she who is something of a bete noire among the anti-PC brigade, that took her attack on the Treasury chief secretary at Labour’s Scottish conference from ‘oo er’ to ‘oh my God, she’d better apologise.’

When you look at the rather fine dark strawberry blonde locks atop my head, it may surprise you to learn I was once a ginger. There is one childhood photo in particular where I could pass for a young Charles Kennedy crossed with a young Mick Hucknall, if you can imagine such a thing. So till my early teens, when my hair started to darken, I was quite used to the insults that – for reasons I never fully understood – get thrown at redheads.

But – and here is another reason why Harriet may not have been as alive to the sensitivity of the Alexander crack as she should have been – I noticed that it tended only to be male redheads who got the abuse. There was something a bit glam about ginger girls, but something eminently pisstakeable about ginger boys.

I thought Danny Alexander dealt with it quite well, tweeting that he was proud to be ginger and that rodents often cleared up other people’s mess.  But that he has ratted on a lot of his election promises is nonetheless true, and it may seem odd, I pondered as the rain started to leak out of the top of my shoes, that it is the ginger bit that was deemed offensive, not the rodent bit. If she had said ‘Treasury rat,’ or ‘Lib Dem rat’ or ‘former national park press officer rat’, that presumably would have been just about ok. It’s all in the ginger.

We are maybe still a bit squeamish in the UK. My favourite hair jibe came from former Aussie PM Paul Keating who, under attack from his black-haired opponent, shouted back ‘The right honourable gentleman should calm down before he has a heart attack. This is no spring chicken here, Mr Speaker — I knew him when he had grey hair.’ Cue collapse of stout fellow, another win for Keating, and certainly no apology.