It is an undeniable fact that some people always stand too close. Even on crowded public transport, there is inescapably close and threateningly close. When someone steps over that invisible line, when you start to feel troubled, you want to step backwards away from the space-invader, and you focus less on what they are saying than on how close they are to you. The trick here is not to back away but to somehow create a whole new space: turn to wave hello to someone passing, turn away to get something out of a bag, at the same time subtly putting some clear water between you and the invader.

If you suspect that you are the person that unknowingly is the space-invader, then apply the following test: if you can feel the warmth of their anxious breath upon your face, then you're standing too close.

We are becoming increasingly unused to sharing our personal space. Communal living outside the family unit is at an all-time low - so that people don't even get to practise their space-sharing skills on flatmates. We are so insulated from the outside world by our iPods, mobile phones and our fear of catching an aggressive stranger's eye on the street that it is rare for anyone under the age of 40 to even acknowledge their physical environment.

Social networking sites remove us one step further from actually having to interact with people; but even that virtual personal space is being increasingly invaded - by Big Brother companies who dig out every personal details they can to establish our voting preferences, our retail profile, our ability to finance mortgage payments.

Employers now have a propensity to invade would-be employees' personal space by checking out their social networking site . . . unearthing every embarrassing picture, every drunken posting, which then prejudices their hiring decision. Even online, guard your privacy in the same way that you would in 'real life': apply the same judgements to making friends, or even 'catching someone's eye' as you would in the outside world.

We need to preserve our personal space, both in the real world and the virtual one, but not at the expense of any intimacy at all. So get out there and start interacting with people - just don't stand too close.

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