I WONDER if people have children because they have not enough faith in the quality of their friendships.

Children are a lot of work, reportedly, but you have the (predominantly) inescapable bondage of blood.

One fear of being childless is of being alone, at the end. Children are some sort of guarantee that when you need it most you will have, at least, visitors and pot plants.

Relate, the relationship charity, reports the findings of a survey that shows as many as 10 per cent of people in the UK - about five million adults - have not even one close friend. Certainly, the thought of five million people in this position is saddening, but not a cause for pity.

Presumably many of these are elderly or have suffered bereavements. Some will be hostage to circumstance and some delighted in their solitude.

Not everyone takes comfort in the counsel of others.

Robin William's Mork, in Mork and Mindy, discussing loneliness, comes to the conclusion that humans bring the condition on themselves. "You see, when children are young, they're told not to talk to strangers. When they go to school, they're told not to talk to the person next to them. Finally when they're very old, they're told not to talk to themselves. Who's left?"

At this age, the age when you are supposed to have the most varied circle of friends, it is difficult to imagine a life without.Of course, there have been ­disappointments. There have been friendships that came about through circumstance, through proximity and through shared experience, which, though ill-founded, still caused pain on ceasing.

There are friends who have married and retired from friendship. Those who were only interested in socialising as a means to an end and now, settled, they are no longer in active service. They have someone contractually obliged to chum them and, Christmas cards aside, are not interested in friendship. At least, not until the relationship ends and they need support from those they have neglected.

There are those who are truly dear but are taken overseas for work or for love or for adventure, and those who do not physically move but who change so greatly that there may as well be an ocean or an aeon between you.

So, yes, it's hard to imagine a life without friends but easy to see how it could happen. You like to think, youthfully optimistic, that it will never happen. That if you expend enough energy now, the dividend will be to always have your people around you. But what if energy is not enough?

Friends are the people you can take for granted without really taking for granted. That you can confidently ask a favour of, knowing you will repay it amply. That you can go a week or two or three without calling but, when you do, they will pick up.

Those who become family, but ­without the shared DNA.

I am fortunate enough to have made my own family of friends but I do, quietly and rarely, wonder if they too will move or change or become swept up by familial responsibilities. You can be so confident in your relationship and then, a disappointment.

Friends should be the people who irritate the hell out of you but who you still want to be around. Those who make you a better person by their perfection or their flaws. Need is not a grubby bolster to a friendship but should not be its foundation. The same is true of flattery and status.

Through humour or fury or ­doltishness, a friend should entertain. They should learn when to give offence ("Your new boyfriend is no good") and learn to let offence go.

It's your own choice whether to ­overlook any or all of these qualities for the sake of company but, crucially, remember that fear of loneliness and friendship are not the same thing.