“Sir” – The speaker is required by the terms of his contract to pretend it is a pleasure doing business with you.
“Mate” (1) – Is the speaker your actual mate? If so, this is a bit formal. He may be about to give you bad news.
“Mate” (2) – Is the speaker a stranger? You are about to be hit.
“Chum” – You are about to be hit by a UKIP voter.
“Old boy” – A UKIP voter is about to ask you to do something.
“Chap” – A media executive is about to ask you to do something which you will be required to find charming.
“Squire” – You are about to be cheerfully overcharged by 100%.
“Boss” – The speaker will tolerate nothing less than immediate payment for the service he is happy to be carrying out for you.
“Chief” — Like “Boss”, plus the implication that the speaker is a man of sudden, extreme violence.
“Skipper” – Like “Chief”, plus the implication that the speaker has a car boot full of stolen goods at very reasonable prices.
“Guv” – The speaker defers to you in all things, so whatever comes next is really your idea (eg sexist joke, institutional racism, systemic fraud).
“My friend” (said in a foreign accent) – You are perfectly safe in this minicab.
“My friend” (said in an English accent) – You have been identified as a dangerous outsider and are being watched.
“Buddy” – The speaker wants to borrow something he will never return (eg wrap of cocaine, credit for your last fortnight’s work).
“Fella” — You’d better like football and tits or this is going to end badly.
“Guy” – You’d better be interested in house prices or this is going to end badly.
“Geezer” – The speaker will tolerate nothing but top bantz from now until the pub closes.
“Pal” – The speaker has one fist clenched to hit you but, worried you might hit back, reserves the right to pretend it’s the 1930s and everything’s fine.
“Brother” – The speaker is stoned or drunk to the point of helpless amity. You are in no danger.
“Bruv” – The speaker is stoned or drunk but may turn at any minute. Keep your wits about you.
“Son” – The speaker is about to give you advice which you both know you’ll ignore.
“Lad” – The speaker considers you and his sheepdog loyal friends.
“Bro” – Are you sure you’re in Britain? We don’t really use that word… wait a minute, does the speaker have red trousers and majestic hair? Ah, he just came from Eton. What he means is ‘chum’.
“Homie” – Like “Bro”, except the speaker left Eton in the ’90s and now drives a Mercedes S-class.
“Darling” – The speaker went to RADA. Don’t expect to get a word in edgeways.
“Blud” – The speaker wishes you to know he’s got your back in a gun or knife fight. Most commonly said into mobile phones while standing in queues for chocolate milk.
“Cuz” – The speaker will be round your house this weekend to take gangsta selfies and watch Britain’s Got Talent.
“Man” – The speaker feels a fuzzy companionship with you as a human being, even if you are currently arresting him.
“Dude” – The speaker would rather pretend it’s California than risk choosing the wrong mode of address.
Your surname – The speaker learnt personal relations in public school, army or police. You’d better do what he says.
Your surname with a Y on the end – The speaker holds you in genuine regard and will gladly hold your pint while you have a slash in a hedge.
Your first name if it has more than one syllable – The speaker does not yet know you well enough to shorten your name or assign a new one.
Your first name with an O on the end – Your deep and lasting friendship with the speaker depends on neither of you ever doing anything gay.
“You daft twat” – The speaker has no secrets from you, loves you like a brother and at some point tonight will awkwardly man-hug you.
“You c***” – Hard to call. Pretty neutral language; a bit over-familiar, maybe. You’re probably fine.