plant ID please

I have this plant in my front garden and to be honest I thought it was a weed but i dont know. Its only about 5 inches high i think (i am at work now and have a bad memory!) and the flowers are about the size of a five pence piece and are a pink/purple colour. Its very pretty though even if it is a weed!

 

Hi, It looks a bit like Herb Robert, though the flowers are usually a bit pinker, I think. Also I don't think Herb Robert has a very nice scent so you may be able to tell by giving it a sniff..