This pattern dates to around 1957 - and is a fantastic piece of mid-century modernist British ceramics.
This is one of Midwinter's harder to find patterns - called Quite Contrary, and it was designed by Jessie Tait - as annotated on the base of each plate.
They are each 7 ½ inches in diameter.
Three are in really good vintage condition with no nasty chips or cracks.
I am also listing four matching shallow bowls on my site - would try and get some postal discounts on these it you want the two sets.