It's the unspoken dilemma dividing Britain - one kiss, or two. Once the preserve of family and close friends, the peck on the cheek is creeping into all walks of life. But no one is sure when it's suitable, and how many are appropriate.
Greeting used to be a straightforward handshake, but not anymore.
You offer a hand and you get a cheek.
You give a nervous peck and then as you pull back you get offered a second cheek.
With the other person hovering awkwardly on their front foot, you go back in at speed to finish the job, leaving you both blushing and giggling in embarrassment. At least a clash of heads was avoided.
Welcome to the social minefield of greeting in 21st Century Britain - how to judge the expectations of the other person, without appearing over-familiar or uptight?
David Cameron showed how deftly it could be done when responding to the unexpected second cheek offered by a woman he met in Oxford (see video, above).
But sometimes the wrong form of greeting can cause offence and provoke a diplomatic incident, such as when former French president Jacques Chirac refrained from his usual hand-kissing when he met the then Foreign Secretary Margaret Beckett.
And now the chaotic practice of hugs, shakes and kisses is sowing confusion in the once-stuffy business world, where not long ago taking off a tie raised eyebrows.
The start and end of meetings with clients can be excruciating, says Rebecca Williams of CHA, a workplace communications consultancy.
GUIDE TO HUGS AND KISSES
The handshake is always fine, even with a stranger, says body language expert Judi James, but eye contact is important.
The air kiss should only come after you've shared a social discussion, such as lunch with a client. Two is becoming common.
The Sopranos hug-and-pat is increasingly common between businessmen and says "alpha-male". No pelvic contact.
The lips-to-lips is creeping into some industries but is unhygienic and rarely appropriate in the business world.
The hand-kiss favoured by Jacques Chirac could be seen as an insult in the UK and usually prompts giggles.
"There's a moment of tense awkwardness when a person leading the meeting kisses a client and everyone else gets a bit anxious - what do we do now?
"Once two people kiss, they set a precedent and then we all have to kiss everyone. It can be really uncomfortable but protocol dictates that we have to."
People working in public relations usually go for two kisses, she says, but it can depend on the nationality. In her experience, Americans don't kiss, Argentines have two and Parisians four.
"We've no set number of kisses in the UK. A kiss on one cheek might be fine but sometimes you go for two because we've started to adopt other cultures. It all feels very unnatural."
The British weren't even good at the handshake and now there are other options like hugging, air kissing and even lip kissing, it's a minefield
Judi James Body language expert
She says she keeps a mental note with different clients, to avoid causing possible offence by accidentally "downgrading" a relationship from kiss to handshake.
This is an absolutely vital issue, says body language expert Judi James, because a greeting sends out signals of status and charisma and says a lot about your personality.
"The British weren't even good at the handshake and now there are other options like hugging, air kissing and even lip kissing, it's a minefield."
This confusion has inhibited people because they are scared of getting it wrong, she says. Her quick guide is that handshakes are always fine, while kisses should be reserved for people you have some kind of social relationship with, even if that's just a client you've shared lunch with.
Two kisses has become increasingly common but some people find that embarrassing and in France one is more intimate than two. Never say "mwah, mwah" because it smacks of insincerity.
It's not the first time the British have got into a muddle by adopting continental mores without any established convention.
"Someone needs to lay down the law - a handshake with anyone, air kiss after three meetings, two cheeks and the right cheek first, play golf together and you get a man-hug."
Honecker famously kissed other heads of state
While men commonly practise the kind of hug and back-pat seen on The Sopranos, there is always an avoidance of pelvic contact, to remove any sexual dimension, she adds.
There was, however, no such red-blooded reserve practised by former East Germany leader Eric Honecker, who famously kissed Leonid Brezhnev on the lips in 1979, an act which was immortalised on the Berlin Wall.
Organisations should clearly set out the expected levels of intimacy, especially between junior and senior members of staff, says Mark Millard, a chartered psychologist who helps firms and individuals improve their well-being.
And one of the reasons why the British get so flustered about this, he says, is because they inflate the significance of a kiss compared to their neighbours.
But don't think the UK is becoming more intimate, says David Pendleton of business psychology firm Edgecumbe in Bristol.
HOW MANY KISSES?
Three: Brittany, Netherlands, Belgium (if other person 10 years older), Egypt, Russia, Switzerland
Two: Spain, Austria, Hungary, Greece, some parts of France
Close friends and family only: Germany, Italy, Middle East (except between male friends)
Don't try it: Japan (bow)
He believes kissing is a sign the UK is merely absorbing foreign trends at a dizzying rate while also being in a hurry to do everything, including forming relationships.
The confusion comes because there is a push to be more intimate at work - through exercises like team bonding - and a pull in the other direction from people hugely afraid of breaching equality and sexual harassment laws.
"If we were heading for a more intimate business world, it wouldn't be confusing, we'd be hugging each other to death. But at the same time we see people massively nervous of anything other than a handshake."
So what's the best way to play it, in the boardroom and in life generally?
There are other ways to break the ice, says Mr Pendleton, such as a joke or a broad smile.
"People can be smiley and warm while being mindful of the kind of personal space issues that people need to work within. Kissing is not the only sign of being confident and relaxed."
A more succinct rule of thumb might be - be yourself.
Here is a selection of your comments.
After spending a week with some of my friends, all of whom kiss when saying hello and goodbye, I went out with some old friends of mine. Thinking I'd be proactive and friendly, I went to kiss one goodbye. She recoiled in horror, fearful that I was hitting on her, and told all of her friends about it! Talk about awkward. Richard Bridger, London, UK
In Eastern Turkey when you know another guy and you meet him again a hug and kiss on each cheek is expected especially in business circles. This is difficult for us conservative Brits where we are hung up about bodily contact between males unless we score a goal in football!! Richard Baker, Diyarbakir Turkey
Never mind differences between countries, in Brazil there are also differences between cities. In Rio it's two kisses, whilst in Sao Paulo it's one kiss and even that isn't totally reliable due to the movement of persons between the cities. I now go for one kiss on the right cheek and if that's wrong make a joke of my doubt. Phillip Newman, Currently Sao Paulo, Brazil
I live in the UAE and I have to say the Arabs kiss more than anybody else on the planet. We kiss like crazy, kisses on the nose on cheek, on the hand, and the shoulder. It varies from country to country. It's getting out of control! The only people I would kiss on the cheeks are my parents. Rashid Mohamed , Dubia
Seems like a middle-class thing to me. For working-class people like myself, you're lucky if there's any eye contact; let alone any physical. Russ Swindle, Maldon , England
Having lived my whole life between England, Switzerland and France, I now tend to greet people initially, as I approach them, with a handshake. As I walk closer in towards them, and if we have met once before, this is usually then smoothly followed with kisses, no airy nor slops, straight forward pecks - one to each cheek, or if family / close buddy then it could be three (pour la Suisse!) or four (pour la France!) - whilst still holding their hand. But I never do one kiss - feels unfinished, almost insulting. But then I am female! I expect and like kisses......... Anne, London
Here in this part of France the norm is four, but three miles down the road in a different department/region it is two, and in other areas it can be three. The kids when meeting a large group of friends usually just do one. John, Saumur, France
I'm reminded of a piece from "The Men from The Ministry" when they need to prove that they were British...
"What would you do if a strange woman came up and kissed you?"
"I would apologise at once!"
"They're British" James, New York, NY
Don't forget that goodbye kisses can differ from greeting ones! My girlfriend's mum is Brazilian, and I often get the two kisses for hello, and one for goodbye but unfortunately this changes randomly so I always approach with much caution and see what happens. A lesson I especially learnt when I went to greet her French partner with a nice handshake. He went for the kiss and I ended up sort of pecking him on the lips...suffice to say a firm handshake is now our standard! Kieran, London
I come from Switzerland. Even there it's not always entirely clear. I had no idea, when I first came to UK, how many pecks to give. It always ended in the rather awkward "oh.. oops, sorry." Daniel Einars, Colindale
I think it is fantastic that the great British reserve has loosened up on greeting friends and family with the two kisses. Much more friendly and cosmopolitan. I agree that a more formal handshake is appropriate in the appropriate circumstances. I used to work for the Leader of the Council in a local authority as her PA and we often greeted one another by offering two kisses. Fantastic Christopher Hall, Prestwich
This whole multiple kissing thing is utterly ridiculous. We're British; a firm handshake will suffice. Clifford Hayes, Hastings
Try Bermuda! Hand shaking is the way to go. Between men it gets complicated. Concentrate now....firm handshake...slide hands apart while maintaining contact all the way down the fingers...grasp the fingers(now hooked over)...at the same time rubbing the thumbs together...pull hands apart....form a fist....touch fists gently but positively. By which time the ice in your 'Dark & Stormy' has probably melted. Michael Swain, Hamilton, Bermuda
Two kisses in the social arena, one kiss for people you are close to and handshakes when on business is my rule. It is more difficult for colleagues - I tend to kiss those I am close to twice but only on social occasions. Andrea Guerra Fernandez, Southampton, UK
As a child I have always travelled and seen many cultures.
I remember being in shock after my French exchange, my French pen pal telling me that I have to greet and say good buy to all the guests with four kisses. That's OK, unless you can't stand someone. I thought I was tactful and missed the person. I was in so much trouble with my pen friend, for missing one of her friends!!!! However I must say after the initial shock it is wonderful to have the warm welcome, a hug and a kiss. They say the French are happier and healthier due to the amount of kissing they do! Elizabeth, London
This is a very real problem, especially when you work for a European company and move around between the UK, France and Germany!
In France I tend to find close colleagues kiss twice, but this will not happen immediately, a bond has to be formed first. Germans prefer a handshake at every opportunity. The British as usual are stuck in the middle and when my French colleagues cheek kiss me in my British office it can be very awkward! A kiss from a Board member tends to be good... although it is still referred to as a "kiss of death" for junior employees! Martin, Newport / Paris / Munich
It's about time the British showed some humanity by kissing friends instead of the ghastly "alright mate?" Cristiano, London
I lived in Argentina for a year and everyone gets one kiss on the cheek, whether they're male or female, family member or new acquaintance. This even happened between doctor and patients! It was strange to begin with, but it solved a lot of awkwardness and I actually began to appreciate it. Some people in England, especially amongst the elderly, can go for too long without actually having any bodily contact with another person. John, Birmingham
I just don't like being forced to adopt someone else's style - like when you go to shake someone's hand and they twist it up in a kind of 'cool' shake. Or when you are forced to multiple kiss someone you've never met. I might like licking someone's face when I meet them but I wouldn't expect them to go along with it. The whole thing is a minefield - I'd rather not meet anyone new now! Simon Evans, London
You should try living in Poland... Pole to Pole, three kisses is the standard. Living with a bunch of ex-pats where zero up to three are all possibilities, anything can happen! Most of us default to three, and hope the other person doesn't pull out midway! Rob Berrington,