Charlie is nearly 5 months old now and is being really good...most of the time!
His biggest problem now is when there is food on the table - he sits and whines and barks while we eat, and given the slightest chance he's jumping up on the table to steal the food.
It's incredibly naughty of him. And my wife is beginning to lose her patience with him. If it continues, he won't be here much longer!
He goes to obedience classes and I explained this to the instructor. Her solution was for me to put the hottest chilli sauce I can find onto a piec e of bread on a plate on the table, tell him to leave it, then leave the room.
Coem back in a minute later and be prepared to let him out of the back door! He won't do it again, she said!
Anyway, I tried this. And now he loves flaming hot chilli on bread!
He doesn't understand it's naughty and so just does it continually.
Any advice?

It sounds flippant, but the best thing to do is shut him safely in another room while you eat. No temptation for him and no stress for you. :-)

As Jeangenie says: separation is the key.  If he can't get to the table or see the food he can't pester you.  Try a baby gate if you prefer not to exclude him completely.  Also, Charlie needs to learn that his food does not come from that area of the kitchen.  I wouldn't try to trick him with spicy food as he is still getting a reward for stealing.  You could try giving him a Kong or other activity to distract him whilst you eat.

Our youngster used to go in his crate during mealtimes - as much for his safety as anything else - he was inclined to amble around and trip us up.  Nowadays both dogs come and go as they please but as neither of them has ever received food from the table they don't bother us.  I've also been quite strict to ensure the children do not interact with the dogs whilst sitting at the table.  No touching, talking, or eye contact seems to work and the dogs just wander off to lie down.  If they do cruise past on the off chance (sometimes if we have visitors who encourage it) they are told to 'go away' - an instruction they understand as 'go somewhere else'.  Interestingly they both reappear when we load the dishwasher and they like to hoover under the table for crumbs!!

Be firm - Charlie will soon work it out :)

Definitely put him out of the way, even if it is just in a crate in the same room. Pups are greedy creatures, but eventually they do learn that if they get NOTHING out of something, it is pointless doing it. In other words, every time he has a chance to steal something, he is rewarded and the behaviour is reinforced, so he will do it even more. With my dogs you can very easily tell what they have learnt- If I eat something, they don't even look at me because they know it is pointless -I don't give titbits when I eat. However they will happily beg off my mother when she visits -say no more, game's up! ;)

Totally agree with what has been said. You must never ever feed him from the table and not even acknowledge that he is there. My two girls literally turn their backs to me when I am eating as they know that this way, they may get a treat when I next go into the kitchen. When puppy came along, of course, she had to learn too. I did keep her in the room but totally ignored her and if she sat and stared at me I would hold a newspaper up between me and her so that she could not see me. After a couple of minutes she would give up and lie down. A bit of a pain but they soon get the message and learn that there is no benefit whatsoever in watching you eat but there might be something good coming later.

I totally agree with all the other posts. i put my newest pup behind a stair gate for the first few weeks as she kept jumping up at the table, when she was their i'd just ignore her while we ate. after this she rarely bothered us at the table and if she did i told her to lie down.
I never feed any of my dogs tip bits and they don't associate our food with theirs, as i keep their food in the utility room. the only treats my dogs get are when training or the occasional bone in the garden.
if everyone follows the same rules and ignores the pup and never gives tip bits when your eating then the pup will soon learn theirs no reward if he sits and waits or begs for it. never leave temptation around either as most your pups will think it's theirs for the taking.
you should be learning some commands at training classes ie 'leave it', which is great as the pup learns that this command means they can't have what your telling them to leave and if you continue training your pup will start to do as ask.
How often are you feeding your pup? i suspect two or three times a day. i always feed my dogs twice  a day, once at 8am and then again at 4pm so they don't get too hungry.
don't give up it's just down to them learning the rules but for now just put the pup behind a stair gate until he gets the message, maybe with a bone so he knows he gets something nice if he stays away but it's not going to be any of your food.           

He doesn't understand it's naughty and so just does it continually.

Ditto, as everyone else has said, just looking at your statement can you not see how funny it sounds, that a pup or dog or any animal is to accept that it is naughty to take food. :-D Of course it is not naughty, we live to eat, a dog is a natural hunter it knows no different from the food in it's bowl to the food on a table top, if it can get to it, it will have it, what on earth is wrong with that - to a dog. :-)

As already suggested keep him away from your food, as he gets older he will get used to the idea that this is not where he is fed from as long as you only feed him in the kitchen, but food is anyones, first to it, gets it. :-)

In time the commands, leave and No! Will have more significance with practise, but food is always used as a training reward so just keep him away whilst you are eating until he is older and understands what you teach him.

Ive a cocker who does not make a sound, only when playing with JAke our other dog, but he is a thief. If I spot what he is oup to and say "NO" he does not pinch things but if I dont see any food is fair game.

Surley you just shut him out at food times? we ensure food is not left where he can get at it, and he's fine. Its when they act as a double act, Jake pulls it down he is a Border Collie and v. tall and they both demolish it!!