My 1-cup measuring cup is 250ml !! 
Both my UK and US cups are the the same.. but it's the pints that are different.
To be honest I use US measuing spoons for UK recipes and really have not had a problem. Then again my way of cooking is hardly scientific and I tend to use weights for baking.
I have even converted some US measurement recipes for bread into metric weight so I don't have to faff about with getting more things dirty. I just plop it on my scale and zero it out as needed.
One bowl makes by DH happy!