It's a wee geranium, possibly invasive but then many plants are.

If you don't want this everywhere dig it out now! Our new garden was riddled with it,2 years later we're still trying to dig it out :-(

Lifes funny eh i have just lifted a load of these on one of my jobs to put in some pots.

It looks very much like Geranium pyranaicum. It does spread itself about readily enough, but is easily removed if not required.

You've got it spot on Fractal...

Sorry to disagree - the flowers are too small to be G. pyrenaicum. However, I do think it's a 'wild' Geranium and needs to be removed. I think it's Geranium lucidum from the shiny leaves.

It looks like one I have in my garden that I keep having to pull up. It is easily removed, but don't let it set seed or you'll have it all over the place!

Spritzhenry - You are right, G. lucidum it is. I failed to note the shiny leaves.

I'll go google Lucidum in a minute, thanks for all your help:-) I remember now, it was a tiny plantlet in with one of the plant I bought last year, possibly one of the 'Orkney' geraniums and I thought I would grow it on as the leaves looked so shiny and healthy. I did think it might be a geranium, but have never seen one with similar leaves. As soon it flowered I was suspicious the flower is similar to herb robert. It's coming out today lol:-)