Our female friendships are undoubtedly some of the most important, complex, and beautiful relationships we will ever have. These women are here for us when we need a shoulder to cry on, willing to sit silently beside us when we’re hurting, ready to talk out our problems at a moment’s notice, and always prepared to give us a little lift when we need it most.

But there are those pals who opt for a slightly different approach to friendship, fusing all the qualities of friend and foe into one. We’re talking, of course, about our frenemies.

These guys are far more likely to offer you negative criticism / ‘tough love’ than a life-affirming quote when you’re feeling down. They drop snarky little barbs like they’re going out of fashion. They call you when they need you, but are suspiciously unavailable when the tables are turned. And, as a result, while we may enjoy their company (in small doses!), our frenemies are far more likely to cause us stress than anybody else.

Time to cut them out your lives for good, then? Well, not according to science.

That’s right: the experts have actually said that we ought to start cherishing our frenemies.

Researchers at the University of North Carolina paired up a group of undergraduates and had them send questions via instant message to one another: half of these were written to encourage, and the other half to undermine the recipient.

‘Frenemies’ (or, to use the scientific term, ‘ambivalent relationship) established, students were then told to edit an error-filled blog post that they were told had been written by their new friend or frenemy (but was actually created by the researchers).

Those who had been dubbed ‘frenemies’ proved to be far better at editing mistakes than those who were simply friendly – and, strangely, were also revealed to feel more empathy towards their partners, too.

So what’s the explanation?

Well, frenemies have a way of getting under our skin in a way nobody else can. As we spend so much time complaining about them, however, we’re always focused on what makes them tick – and we always want to perform better in front of them, too.

As a result, our frenemies push us to work harder and help us to be our best selves. Win.

If that weren’t enough to convince you to keep your friends close and your frenemies even closer, a new study at the University of Plymouth has found that our frenemies aren’t trying to upset us when they dish out all of their negativity. In fact, they have our best interests at heart.

Scientists surveyed 140 adults and asked them about hypothetical situations.

Belén López-Pérez, a psychological scientist and the study’s author, explained: “We identified several everyday examples where this might be the case – for instance, inducing fear of failure in a loved one who is procrastinating instead of studying for an exam.”

They found that subjects who were mean to their partners were more likely to be empathetic (there’s that word again!) and want their partners to succeed.

“These findings shed light on social dynamics, helping us to understand, for instance, why we sometimes may try to make our loved ones feel bad if we perceive this emotion to be useful to achieve a goal,” López-Pérez said.

Davina McCall has previously spoken about her own tough-talking friend and the huge impact it had on her own life.

Speaking about her past battles with heroin on John Bishop: In Conversation With, the TV presenter explained that she accidentally pushed loved ones away when she began her cycle of drug abuse.

“I’d lost all the good people,” she told Bishop. “There was one person left, and she was the one that said to me in the end, ‘Look, we’re all talking about you. You think you’ve got this kind of mask up and you’re kidding us all, but you’re not.’”

McCall went on to explain that her friend – who she chose not to identify by name – told her that she couldn’t be around her anymore, saying: “‘We all know that you're a junkie and we all know you're taking heroin or we all know that you're, you know, you're lying to us the whole time. And I'm not going to stand around and watch it anymore.’”

McCall continued: “She said, ‘I’ve had enough.’ And she’d been there for me the whole time – I just thought that she was going to be the one constant. When she said, ‘That’s it,’ I was devastated.

“Of course, I swore at her a lot and got out the car, slammed the door.”

It was exactly what McCall needed to hear, however, and inspired her to seek help: just a short while after the confrontation, the TV presenter attended her first Narcotics Anonymous meeting - and she has continued to regularly attend ever since.

Images: Rex Features