Helen Mirren's in the pink. We've all been there...

When senior (fat, balding) politicians like Keith Vaz feel comfortable tweeting about the Home Secretary's weight, the scales of public life need to be tipped the other way. So let's take a minute to applaud Helen Mirren gliding down the red carpet at the Baftas, her crop of blonde hair dyed the colour of candy floss. Pink hair on a woman over 60 never looked this good on Barbara Cartland.

Mirren said she chose the colour because she saw it on the winner of America's Next Top Model. For a woman of 67 to copy the hairdo of one decades her junior gives hope to us all, in our culture that would rather older ladies wore sensible shoes, played bridge and complained about the buses.

I had pink hair once – when I was 15. Bored with my blonde hair, and desperate to be "different" at my suburban comprehensive school, I dyed it cherry red – or at least that's what the Harmony hair dye packet said. My hair did indeed start off crimson, but over successive washes it faded to bubble-gum pink, later to a pale rose. It took more than six washes to come out, but I became rather attached to the colour, so didn't mind. It was my own way of rebelling, but in a very tame way – my teachers didn't object, in fact one said she rather liked the way it changed colour week after week. Getting a tattoo or a nose-piercing would have been too radical, and not so easily undone. A butterfly on your shoulder or a cat on your ankle is not out in six washes.

The coolest girl in the class, who had never spoken to me before, said she liked my hair. Her own had just gone from orange to midnight blue. The shock of pink turned me, I believed, into a more interesting, less square, version of myself. I was daring, but not dangerous.

Mirren's motivation for dyeing her hair pink may be to get as far away as possible from her alter ego, the Queen, who I'm pretty certain has never waited for a bus, prefers jigsaws, and wears court shoes. Mirren's rebellion is tame, inoffensive, and rather fetching in February. Daring, but not dangerous.

Above all, Mirren has reminded us that at 16, 40, or 67, pink hair is a liberating change of gear, an opportunity to shake off an association with another person, be it the Queen or a teenage girl quietly (and tamely) protesting against her middle-class life. Since my twenties, my hair has barely changed from a straight, layered shoulder length cut. I have become less radical with age, keen to show that a woman should be defined by more than just her hair, but ultimately abiding by the conformity of the workplace. It is unlikely I would have passed a job interview with pink hair.

Mirren, now defined by her Oscar-winning performance of the Queen, and her reprisal of the monarch in The Audience, can dye her hair whatever colour she wants. Maybe this frees women of all ages to consider pink hair.

Perhaps I should head to Boots in pursuit of a new hair colour – as long as it's six washes out. Better still, Theresa May should dye her hair pink too. That would give Keith Vaz something to tweet about.