It probably isn't available in the UK. Europeans seem to have something against corn for some reason
Recipes call for the use of corn syrup because it doesn't crystallize when re-heated, so candies, frosting, fudge and such will be and remain smooth, not get all grainy from the sugar (sucrose) re-crystallizing.
You can make a simple sugar syrup to substitute for corn syrup. You will need to add some cream of tartar to it which will break the sucrose down into glucose and fructose and eliminate that annoying little crystallization problem.....cream of tartar is used in recipes as a thickening ingredient and should be available in the spice section of your grocery store.
2 cups granulated sugar, 3/4 cup water, 1/4 tsp cream of tartar
Mix together in a sauce pan until the sugar is dissolved in the water. Heat over medium high heat to a rolling boil. Continue boiling for about five minutes string constantly, you may have to run a spoonful or two of water around the edges mid-way to melt down some crystals, but most of the time they don't form, especially if you use a small, narrow sauce pan......I don't know to what temp that would be.....220-230 °F........sorry these are all American measurements.....I can take a stab at converting them if you need that.....
Anyway, if you don't have a candy thermometer you can determine when to quit by using the old, mostly reliable "soft ball stage" whereby you drop a little of the syrup in to some iced water and if it forms into a "soft ball" then it's syrup......and you're done making your corn syrup substitute. Take it off the heat and let it cool completely.......
If you continued cooking the sugar syrup you'd eventually reach the "hard ball" stage whereby a little of the syrup dropped into some iced water will form a "hard ball", yeah, like glass!! Hard ball stage is probably about 250-260 °F
So, I'm betting you can skip the "soft ball" stage along with the cooling and continue to cook your syrup until it reaches the hard ball, glass like state or to whatever temp your making-glass-out-of-corn-syrup directions give.
Shylaah