We cannot get corn syrup in UK it is only used in the animal industry as far as I can make it we do not do a human grade one.
We tend to use golden syrup or treacle but they are not a direct substitue for corn syrup.
Some recipes if the flavour does not matter I have used maple syrup though I do have a recipe for mock corn syrup made with sugar.
In case you are not familar with treacle or golden syrup the following links explain it.
http://www.lylesgoldensyrup.com/LylesGoldenSyrup/default_us.htm
We actually can get this plastic bottle now as well
Origins of black treacle and golden syrup
http://www.recipes4us.co.uk/Specials%20and%20Holidays/Treacle%20Origin%20Uses%20Recipes.htm