Easy peasy ... well not so. Look in the Collins Guide and there are several species so it took sometime to convince myself of this ID.
Stem with 2 ridges (one shown here)
Petals > 2x length of sepals
Perforate St John's-wort
I hope ;)
The next two just for fun.
(Daucus carota ssp carota)
I lve the fact that the central flower is usually red unlike the rest.