‘Congratulations,’ says the doorman, shaking me by the hand as I enter the 400-seat Leicester Square Theatre. ‘You are the 12th bloke here tonight.’

If he’s exaggerating, it’s not by much. This is comedy by demographics, a show for mums about being a mum, from a mum. Former publicist Sophie McCartney has built up a sizeable audience from talking about such stuff online, quickly spawning two Sunday Times bestsellers and now this fast-selling tour.

Unsurprisingly, when it comes to her material, relatability is everything. When she talks about the ‘3,000 WhatsApp messages’ it took to get each friend group here tonight, knowing laughs can be heard across the room. And that’s even before we get to the shared trials and tribulations of motherhood.

Although she mentions her children – ten-year-old son, seven-year-old daughter and a one-year old baby – McCartney exploits the general rather than specific, couching observations as what ‘you’ do rather than what ‘I’ do. 

There are ‘woo’s galore as the audience recognise everything from the joys of wearing Spanx to knowing that describing a child as ‘high spirited’ is code for ‘nasty shit’; from married sex feeling like a chore to being called a ‘geriatric mother’, that heartless phrase medics use for the over 35s. 

That everything she says seems familiar - even to a non-parent like me – is not only beside the point but to miss it entirely. Familiarity is exactly what this audience want. A rare night off from the kids to turn their brains off and be told exactly how difficult parenting is, that their complaints and struggles and frustrations are universal.

This is the point McCartney is making. Being a mother is a tough task, for which there’s no instruction manual but a thousand voices among your peers, in the press, online and in your own head telling you you are doing it wrong.

Her brand of ‘mumcom’ is the antidote to the judgmental NCT class, giving permission to be imperfect. To know you can still love your kids even when - in any given moment - you might not like them very much; to spread some appreciation of an overwhelming job that’s usually thankless.

No better illustration of the realities of motherhood comes from the picture she shares that her daughter took of her on the toilet, exhausted and broken – a far cry from the confident, lively woman in leopardskin catsuit and sparkly mini-boots who prowls the stage tonight. For McCartney is gregarious and animated, especially in a couple of particularly physical act-outs.

But she doesn’t add much comedic spin other than reflecting the audience’s experiences straight back at them. And when she does, it’s usually pretty basic. For example, she likes a euphemism, getting the room to share their favourite slang term for vagina and sharing her own for the cock and balls. 

Speaking of which, more than once does she swing the mic between her legs to mimic her husband’s cock. This is not highfalutin stuff. And mimicking David Attenborough commentating on her life as if a wildlife show is almost as old a stand-up trope as the beloved naturalist himself. 

Mulling over how your social life dries up, she recreates a night out of lore, being chatted up by blokes with frosted tips and wearing Ben Sherman shirts and Lynx Africa, then coming in pissed and trying to negotiate the stairs. It’s probably the most bog-standard, route-one stand-up material there is. Despite that, or probably because of it, it lands well. And McCartney certainly puts her heart into performing it.

For all those lamenting the loss of big nights out, post-children, this show evokes some of that lost spirit, inviting the audience to dance in the aisles to Man! I Feel Like A Woman before we even start.

It underlines the fact this is comedy for those who don’t get out much, so perhaps we can cut McCartney some slack for not being wildly original. But that’s the disclaimer for those seeking something a little more fresh from their comedy.

• Sophie McCartney’s Tired & Tested tour continues until April. Tour dates