Scarlet pimpernel

Walking around work today, I noticed this beautiful Scarlet pimpernel Anagallis arvensis, growing in the grass. I love this common arable weed as it is such a pretty colour! although I have to say when you look at in macro, the glorious bright pink, hairy yellow topped stamens do kind of clash with the red petals, and I have blipped it today to prove this point. 
Scarlet pimpernel is also known as 'Old weather vane' or 'Shepherd's weather-glass' as the flowers close when the air pressure drops as bad weather approaches.