what is half and half?

Half and half has a fat content of between 10.5 percent and 12 percent.

I think in the uk you would use single cream, or unwhipped whipping cream. I have to confess, I always shy away from recipes that have half and half in them as I'm not completely sure of what the equivalent is.... Would someone be able to say what the fat content of half and half is?

Half and half is half milk and half cream. Easy to find in the dairy section of your market. It's thinner than say, heavy cream.