It's all kicked off on Mumsnet.

Splitting the bill is one of the great challenges of modern middle-class times. A friendship or relationship you have with a person is only ever truly tested once you have to go through the trial and tribulations of paying for a meal with them. "But I didn't have a starter." "But he had a the steak and I only had the soup." "But but but...." Now, a woman on Mumsnet has sparked debate once more by posing the question: how should you split the bill when one person hasn't been drinking alcohol? The woman in question refused to split the bill at her friend's birthday dinner because she was not drinking alcohol at the meal. Writing on the UK-based forum, the woman explained that the cost of her food and drink totalled just £19 while celebrating her friend's birthday alongside five others. She said her friend texted a day later complaining that her refusal to split the bill equally, and pay £40, had left the other members of the group upset. Of course, the comments on her post were split. Some backed her up, saying that she was quite right to not pay an extra £21 because she hadn't been drinking. But others argued that she shouldn't have gone if she wasn't willing to split the bill, particularly given that it was a birthday meal. The post read: "I was the only one who didn't drink alcohol. Just a few lemonades. "At the end one person said: 'Should we just split the bill then?' But she didn't say it as a question, more of a leading statement. She then got her phone out and split it six ways. Came to just over £40 each!

"I said, 'Sorry, no. You've all drunk quite a bit and I've had no alcohol at all. Would you mind if I pay separately?'

"They said 'yeah fine'... and the atmosphere was a little odd after that. We all went our separate ways after that. It wasn't a particularly expensive place, but not cheap. Food very reasonably priced but of course the alcohol stacked up the bill significantly.

"I've been messaged my birthday girl this morning to say I was really out of order and should've just split. Everyone was a bit upset.

"Am I being unreasonable to not have split?! I felt like I was being fair there. She also said she was opening her gifts from me in the evening but I've had no words in a way of thank you."

One user responded: "This has happened to me too. Very often, my meal is much cheaper than everyone else's because I don't have alcohol and usually don't have dessert. I always just cough up when the bill is split equally and accept that I have partly paid for other people's food and drinks." Another said: "I would never not just split the bill. Can't be arsed with all that, but I can afford to pay it and if I couldn't I wouldn't go to that particular restaurant/ night out etc. I would also expect to pay towards the birthday person's meal." A third added: "I see where you are coming from but it was 40 quid, I would just have split it to avoid tension and because I rarely eat out with friends. Having said that your friend is a bitch for texting you like that and the others need to grow up if that upset them." But some defended the woman. One person wrote: "As someone who doesn't drink alcohol, I would have said exactly the same. Cocktails and doubles with mixers can be £6-£10 each and my sparkling water is £2." They added that it is "actually very rude to expect a non drinker to split the bill when everyone else has had lots of alcohol."