BabyCentre UK has this to say:
The Department of Health recommends that you should not give your baby cow's milk or dairy products until your baby is six months old. From the age of six months, you can use small amounts of full-fat cow's milk in cooking, for example in cheese sauces or custards. Avoid giving cow's milk as a drink until your baby is a year old, because it is too low in iron and other nutrients. Semi-skimmed milk is not a suitable drink for children under two years old, but it can be introduced from two years if your child is a good eater, has a varied diet, and is of normal weight. Otherwise use full-fat milk until your child is up to five years old. Skimmed milk is not suitable for children under five as it is too low in calories, and essential vitamins.
HTH
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