One of the Papavera, one of the perennial poppies - wouldn't like to give it a name though :)

Oriental poppy of some variety - closest I know of is Papaver orientale Princess Victoria Louise, but that has double petals, not single.

When poppies naturalize such as these have appeared to, they don't normally come true, but a few may. You will find lots of variation and anomalies. To me, they are more fun & interesting than looking at the exact same flower over and over and over...boring.

Thanks everyone!

papaver somniverum or opium poppy.

Not Papaver somniferum, the leaves are typical of Papaver orientale.

Agree with Bamboo and Landgirl P. orientale... I've been looking at some mo images :)