SO, COME on, confess. When was the last time you simmered a mutton bone or a ham hough with onion, carrot, celery, bouquet garni and peppercorns for six hours, skimmed the results and used the stock to make soup?

How many households still have a pot of home-made Scotch broth or cock-a-leekie mulling away on the stove? As for beef or oxtail soup, BSE has made sure that fewer of us would want to use real bones any more. And even those nifty stock cubes don't encourage many modern cooks to make soup when they can just open a tin, or, better still, buy one of the new ''fresh soups'' in cartons for that real home-brewed taste.

What's more, the old favourites like tomato or cream of chicken are losing ground to frightfully posh concoctions, whose labels read like something on the menu of a four-star restaurant. Carrot and coriander, cucumber and herbs, all manner of delicate delectations . . . at a price.

The bags and cartons of ''fresh'' soup tend to make packets and cans seem common as muck. But are they really that much better? And are any of the many variations available in the shops as good as the stuff your granny used to make, or the stuff a good chef will make in a top eaterie?

The top eaterie we chose as the setting for our soup sampling was Restaurant Splash at the Glasgow Royal Concert Hall, where lovers of music, song, conversation and comedy can lunch and dine in opulent surroundings, and where head chef Michael Hughes, formerly of The Buttery, holds sway.

Mike - whose own soup on the day we called was lobster bisque with truffle sabyon - abandoned his kitchen for long enough to savour six soups, ranging from the exotic to the couthy, judging each on its individual merits.

His own keys to cooking involved seasonal vegetables and lots of fresh herbs, and the correct sequence for adding ingredients so that colour and texture are retained.

n Knorr (packet) Crofter's thick vegetable 11/2 pts, 59p

The ingredients included monosodium glutamate and yeast extract as well as the usual vegetables, and betacarotene for colour. ''Oh, you can tell right away this is a packet soup. It's very starchy. There must be a lot of cornflour in it because it's so starchy it sticks to the spoon. The vegetables have that dehydrated taste. Not very nice.''

Score: two out of 10.

n St Michael fresh leek & potato soup (in a bag) 450g, #1.29

This is a vegetarian version, with the kind of ingredients you would use at home, except for emulsifier and soya lecithin. ''It's not bad, but a mite lacking in flavour. Rather bland. If you added some chopped herbs and cream it might liven it up a bit. But I'm not terribly impressed,'' said Mike.

Score: five out of 10.

n Baxter's potato and leek soup (tin) 425g, 69p

Mike: ''It has a dingy colour. The leeks should be added near the end if you're making this kind of soup at home, so that you get the nice green colour. And it's a bit watery. There's not a lot of body to it. But the taste is nice enough. For a tinned soup, it's not bad.''

Score: seven out of 10.

n New Covent Garden fresh soup of the season, spicy sweet potato and butternut (carton) 568ml, #1.89

''This is very good,'' Mike admitted. ''It has a good flavour and it is near enough to home-made to fool people round a dinner table. It's not quite like mother would make, but it's a nice one.'' The ingredients are all natural, with lots of coriander, cumin and turmeric taste. The list also mentions honey. Whey features too. The blurb says the company's recipes are inspired by friends, food writers and farmers!

Score: 81/2 out of 10.

n Heinz Big Soup chicken and vegetable (tin) 405g, 65p

Mike: ''This has plenty of

vegetables, but it's very salty and you'd know it was canned. It's certainly quite a hearty soup with big chunks of carrots and potatoes and bits of chicken. It's a pleasant flavour and would be fine for a lunchtime or supper snack, I suppose.'' Once again, of course, there's monosodium glutamate, cornflour and colouring.

Score: five out of 10.

n Tesco fresh soups salmon and dill (bag) 450g, #1.49

Some very mouth-watering ingredients are named - smoked salmon, creme fraiche, double cream. Modified starch presumably supplies bulk. Mike was impressed. ''I love this one. With a touch of brandy and cream you could serve this up to guests at a very posh party. There is a real spicy taste, plenty of salmon and lots of dill. The colour's nice.'' Actually no spices feature on the label, but the garlic, dill and tomato must have given it that bit of zing.

Score nine out of 10.

Tesco took top honours, and all three of the ''fresh'' soups were acceptable, though Marks & Spencer's rating was surprisingly low. Baxter's had a creditable score for a tinned soup, the poor old packet of Knorr's didn't make much of a mark. The benefit of the tins and packets, however, is that you can keep them on the shelf for ages, whereas the fresh ones have to be used by the following day.

The St Michael's bag instructs users NOT to freeze the soup, while Tesco's and Covent Garden's can be frozen (on the day of purchase) and used within one month.

One bag/carton would serve two, which means if you did use it for - say - six people, Tesco's would cost you #4.47, plus that dash of cream or brandy! I'm afraid I haven't managed to work out how much it would cost to buy smoked salmon, creme fraiche etc and make your own. But I did taste Mike's lobster bisque and gave it a personal 10 out of 10.

n Dates to watch for at Glasgow Royal Concert Hall are May 17: Gala Scottish Prom, in aid of Tak Tent Cancer Support; Douglas Hurd on Are Politics Dull? on May 18; the early music of Medieval Babes on the May 23; and some amazing flamenco on the May 29. And Mike's soup any day.