Thanks for the reply and it is true that he doesn't want to seem uncool, by being seen learning in front of his buddies. He has said that he would rather be taught by somebody else, other than his 'owd feller' so that is the route I am going down. Kids aren't half awkward
If it's purely the mechanics of riding, the balance and so on, he can teach himself, once you tell him how, and probably master it in an afternoon. Here's how.
Take the pedals off his bike, and show him how it's done, and how to refit them.
Go somewhere where there is a nice big flat area - empty carpark or similar (or perhaps a local industrial estate at a weekend when it's very quiet). Put the saddle down so that he can straddle the bike with both feet down comfortably. Tell him he should scoot the bike round, walking at first, then building up speed so that he's 'running' it along. With each pace, as his feet are off the ground, he learns to balance, and he'll also be able to practice braking and steering at the same time.
When he can confidently run along, and then lift his feet and freewheel (if you can find an area with a slight slope to coast down, that helps), then you or he put the pedals back on, and scoot off, and pedalling will come naturally. The saddle can be raised as he gains confidence.
I taught a chap in his 40s this way. From not being able to ride, to pedalling a bike round, was less than an hour. It varies of course, he may need a little longer, but if he wants to do it, he'll do it. The advantage of this is that you can leave him to get on with it, which he might appreciate, and if you can find somewhere quiet, there is less embarrassment from onlookers. Plus, the sense of acheivement of doing it himself. You might want to be with him, but sit and read a book or something so that you're not tempted to watch and offer advice.
Once he can actually ride, of course, it's worth looking into local instructors for road training - and remind your son that a good cyclist probably makes a better driver when the time comes...
Good luck to you both!