Ensure, meal replacements?

I'm looking for a product like Ensure/Pediasure, which is sold in the US.  Ensure is a meal replacement shake that is frequently used to assist in weight gain for elderly patients or skinny kids.  Does anyone know if something like that is sold in the UK, what it would be called, and where I could find it?

Thanks.

I  may be wrong but I do think that I have seen Ensure here, maybe with the baby formula.

June

Thanks June.  I'll have a look. 

I also found an NHS booklet explaining "Nutritional Drinks" and learned that the brands offered here are Build-Up, Complan, and Boots Recovery.  It said that they should be available at most major supermarkets and chemists.  We'll see what I can find.

Carrie, you can also try Fresh & Wild (Clifton triangle), I forget the brand but its one that Whole Foods sells in the states.  I like the chocolate one. 

Ensure is sold in the UK.  You can also find something similar called Fortisip, and if it is for a medical condition, it can be via prescription as well.