Mumsiness repels me.

I was sitting in the Botanics trying to read some 'hillbilly noir' about meth and incest when a parade of chattering mummies trundled past calling out the faux-Victorian names of their offspring. It was most off-putting. And it is only the yummy mummy type who assault you with their self-importance. There were plenty of hipster dads around that day, in their cargo pants and Birkenstocks, but they can air and water their brood without the world knowing about it. It's the mumsy types who claim space and attention and who flood social media with endless scan photos which always - always - look like curled aliens.

I have no problem with the idea of motherhood which seems to be a mighty brave thing but I loathe mumsiness. I fear its soppy warmth. I fear its choking sentimentality. I fear thickly iced cupcakes with tiny bootees on them.

Maybe it's a hangover from my long single days when I perhaps had to subconsciously steel myself to the fact that I might never be a mother. Whatever the pop psychology reason, I actively fear the deadening hand of 'mumsiness'.

So I was quite keen to watch this documentary - My Granny, The Escort - as it seemed to be about rejection of that kind of identity. It featured three older women who work as escorts; selling what they laughingly referred to as the 'mature lady experience.'

Sophie was a bright and giggling 50-something. She had an unhappy marriage and a bunch of children but she 'did the right thing': she kept quiet and raised them but the moment her youngest child turned 18 she said that her parental responsibility was over. She was no longer cemented in the role of 'mum', so she went off to fly planes and take up sword-fighting. She had a long list of things she wanted to do, she said, 'but the main box I wanted to tick was sex.' So she became an escort, as that was a sure and immediate way to obtain lots of the stuff. And why shouldn't she? She lands her plane and puts down her sword just long enough to indulge in lashings of sex and good luck to her! The only sad thing was that she had to wait so long to do it.

She had gloriously thrown off the burden of 'mum' although the camera seemed dreadfully keen to capture her making tea, as though this was a sly hint that behind her glamour and her pilot's licence she was still a British, middle-aged woman. Look at her, making tea, like every other mum!

In fact, the only concession Sophie made to her life of lust and swordfighting was when she admitted 'because my whole life is sex I've decided to take Sundays off.'

The show also featured Beverley, a glamorous woman in her 60s. She was smiling and confident and had some brilliantly shocking anecdotes. She had started escorting as she needed money but soon found she enjoyed it and so carried on, gladly.

As she described her love of sex we saw a picture on the wall behind her. It was one of those hideous, sentimental things: the word MUM spelled out in pink romantic script, with cherubs clinging to the letters. The mumsy-types who surrender their names to just become 'mum' appal me and so it was brilliant to see sparkly, confident Beverley standing beside this awful picture, as she told her wild stories.

I'd gladly have smashed that picture from the wall, as it promotes the idea that mothers are sexless, dim, obedient creatures. The Angel In The House was thankfully murdered decades ago but today's soppy tide of 'full-time mummies' on Facebook is hauling her back up out of her grave. So we need to give a voice to bold and lusty women like Sophie and Beverley because society says older women shouldn't be sexual: they should be efficient and dutiful and prim. They should drive people to places. Most importantly, they should be low-paid, part-time workers in our nation's great call centres and hospital corridors.

One man in the film summed up this approach - although it could also have been voiced by the cherubs, or the sentimental moron who purchased those cherubs - 'women of that age shouldn't be doing this. They're outside what's expected of a grown-up lady.'

So, throughout, I was cheering for Beverley and Sophie and their rejection of the mumsy lifestyle - but even I felt a tremor of discomfort when Sheila appeared onscreen.

Sheila was 84, dressed in a velour tracksuit and slippers and she inched her way across the carpet on a walking frame. She was frail and hesitant in her speech, yet told the camera she loves sex and she feels proud that she has looked after her body and is still desirable to men.

I looked away. I put my hand over my mouth. I felt uncomfortable watching Sheila, but why? Her mind seemed perfectly sharp and she was using that independent mind to choose a life as an escort. She said she enjoyed the companionship but her main reason was that she enjoyed sex - simple as that! But instead of thinking she was daring or cheeky or bold I just felt sad.

Why did I feel sorry for her? At the age of 84 she is still active, is earning a lot of money, is still perky and attractive, and is enjoying sex - so who am I to feel sorry for her? It's rare that I'm ticking any of those boxes, yet old Sheila has them all.

Would I have felt easier if she'd been sitting behind closed curtains waiting for her carer to arrive? That's no kind of life but it would have made me, and probably others, feel a lot more relaxed. And for all my brave talk that's the saddest thing of all.