Susie Mesure: Who said the sisterhood was dead? The BBC

As a 50-something host of a flagship BBC show, Countryfile's Miriam O'Reilly belonged to that rare breed of lesser-spotted, multi-wrinkled, greying broadcasters that are so hard to spot on the box these days. Note, if you will, the past tense: with unconscious irony, since she was the presenter of a show that marks nature's fleetingness, O'Reilly's career was cut short when her bosses decided hers was the rare species their programme could do without.

Or more specifically, her female boss Jay Hunt, the then BBC One controller, who, O'Reilly told a tribunal, "hated women" enough to sack her and three female colleagues. The quartet, all over 40, were shown the door just in time for Countryfile to move from its Sunday morning slot to a peak, evening window, where even urbanites caught the odd episode.

A coincidence? Hardly, according to O'Reilly, or at least not when you're also told that your crows' feet are one bird's appendage your bosses don't want to broadcast in high definition. Or that the colour white is fine when applied to snowdrops, but rather less so when it's the shade of someone's roots. A female presenter's roots to be precise. (Her former co-presenter John Craven, got away with his hair being whiter than the whitewash on the wall. And being 68.)

It was Hunt, too, who replaced Arlene Phillips with someone less than half her age – Alesha Dixon – as a Strictly Come Dancing judge. It seems that the old truism that other women are often each other's harshest critics has legs, perversely sometimes making it harder for a woman to work for a female boss than a male one. Especially one with a different opinion on balancing work and family. Where Hunt juggled "shift work, long hours and a new baby", the then 30-something O'Reilly felt her two children needed her more than her viewers, so stayed home with them.

Now, 13 years after returning to work aged 40, O'Reilly is again without a job. But instead of getting lost among the 5,000 women who have left the media industry in the last three years (compared with 750 men), she is suing her former employer for age and sex discrimination in one of the highest profile cases yet.

Already the tribunal has heard how O'Reilly was asked whether it might be "time for Botox" or if she'd like a can of black spray dye to cover the "white gap" at the back of her head. Natural, it seems, only goes so far on a nature show.

Worryingly, O'Reilly's treatment reflects an accelerating trend of women being victimised for their advancing years. It highlights the need for the coalition to make it easier for people who have been doubly discriminated against – in this case O'Reilly asserts she suffered because of both her age and sex – to bring a claim by adopting the new dual discrimination legislation that was part of the Equality Act. As things stand, the Beeb just has to show it employs plenty of older presenters or lots of other women to dodge O'Reilly's bullet.

In a world where women – and men – will be required to work well into their seventies, it is particularly absurd that someone as well qualified and respected as the award-winning O'Reilly gets cast aside for a younger model, despite having a good two decades left in her. And her case has come to court just as the grandes dames of Strictly – Ann Widdecombe and Felicity Kendal – are helping the dance show keep pace with ITV's X Factor when it comes to ratings. What's more, the BBC's actions send a dire message to younger women struggling to balance a career with motherhood.

When will male bosses – and, sadly, they are still invariably male – learn that their female colleagues need to be rewarded for the sacrifices their gender forces them to make, rather than punished for something they cannot help, like ageing?