Your mobile rings:

'Hi. It's me. Fancy a pint tonight?'

'Yeah. Down the pub with the lads?'

'No. Thought we'd have a quiet drink by ourselves ... I've got

something to ask you ...'

Words like Man and Best immediately spring into your mind. And, of course, you are right.

Your mate got engaged last week and you were half expecting this call. But unless you've already carefully thought things through, you'd be wise to lose your signal for a while. You need some serious thinking time.

Being a best man is not rocket science. But it does require a real commitment. Before we get into the pros and cons - that's fors and againsts, not tarts and baddies - of saying 'I do' to your amigo, let's have a little history lesson.

When your great-great-(and about another 50 greats)-grandfather decided to take a wife, he meant it literally ... and usually from the next village. It was a case of the other man's grass is always greener ... and his totty is always hotter. So over the hill the horny hun would hike – weapon in hand – to sweep a young maiden off her feet. Problem was, the menfolk of the female's family had other ideas and would give the young upstart a kick in the nuts and send him packing.

Your beloved ancestor soon got fed up of applying ice packs every Sunday morning, and decided it would be more sensible to go in mob-handed. He'd pal up with the baddest brother in his village and then invite him to be the chief henchman on his next amorous quest. This time it was the lass's brethren who got a good kicking as your great-great-(and about another 50 greats)-grandmother eventually got picked up. The old chap had indeed chosen the best man for the job ... and without him, you wouldn't be around today. I didn't realise family history could be so much fun. Here endeth today's lesson.

Nowadays the best man's support is more moral and emotional than physical. His intention is to toast the bride, not roast her father... to slay the in-laws with rapier wit, not his rapier. With more refined duties, however, come greater responsibility. And with greater responsibility comes far more opportunities to cock it up.

Which of these is you?

One guess which one I'd want to do the business for me. Best Man 1 is really Worst Man 1. No one is expecting a Mr Perfect, but the bottom line is that you shouldn't accept the role unless you are going to give it your best shot. And your bosom buddy must think your best shot is good enough or he wouldn't have chosen you, would he?

MAKE YOUR MIND UP TIME

Let's face it, unless you are browsing in WH Smith (other bookshops and internet suppliers are also available), the odds are you have already decided to say 'Yes', or you'd hardly be reading this literary masterpiece. If you're still not sure though, sleep on it. But don't leave it too long to decide. It would be rather embarrassing if you were to accept next Wednesday, when someone else had been given the job on Tuesday.

Had a good night's sleep? Good. And you're going to do it? Great. Your signal has been mysteriously restored ... phone your mate back and agree to that drink. You need to convince him – and everyone else concerned – that you are 100% committed to being the best best man you can be. They can't ask for more than that. Thank him for choosing you (assuming the something he wanted to ask you wasn't to borrow your wheelbarrow). Congratulate him on finding such a fantastic woman. Remind him that you are available to help them both with the wedding preparations in any way they want. Suggest the three of you get together soon to get an idea of what sort of wedding they're planning and to discuss your role in the months to come.

MEET THE EXTENDED FAMILY

Traditionally, your next job would have been to meet the four parents. But the world has changed. The nuclear family of mum, dad and two or three kids no longer exists, if it ever did. Today, families often come with a mum, dad, step-mum, step-dad, siblings, step-siblings, and even step-step siblings ... family trees often have more branches than the NatWest. And at the same time an ever-increasing number of these extended families are scattering themselves all over the country – and often all over the world.

Given these sociological and demographic trends (that was the social science bit), it is hardly surprising that for a twenty-first century best man it can be a nightmare to know who (and sometimes how) to contact, and possibly who not to. What is the pecking order when it comes to seating arrangements, etiquette and all that? Get it wrong and you will cause a diplomatic fallout that will make the Middle East look like a picnic. If you are in any doubt, you simply must ask the bride and groom.

Try to meet (or at least phone) the parents/guardians/persons nominated as the main players by the happy couple. Give them plenty of positive messages and vibes. It's a bit like going to a job interview. What qualities and abilities are they looking for? Be prepared to give at least one example of a time when you have been:

• Cool under pressure
• A great organiser
• A model of common sense
• An effective communicator
• Punctual
• Responsible
• Thoughtful
• Tactful
• Presentable
• Sober(ish)

Well done, young man. On behalf of both families, I hereby declare that you are the best man for the job.

Now prove me right.