What is this brown leaved plant with yellow flower

Hello, does anyone know what this perennial plant is please?  It forms a clump similar to Phlox and has chocolate coloured deep veined leaves with very delicate yellow flowers.

 Many thanks.

Is it Lysimachia?

Not sure it's lysimachia. I have it in my garden will see if I can find the label.

I would say that I have this variety of Lysimachia, I think that it is called Firecracker.

Yes it is Lysimachia "fire cracker" and there are several versions of it for  hanging baskets too.

I have it - it bulks up and spreads like mad 

Definity lysmachia, great but can make an awful lot of itself - we have a small one in a hanging basket but will try and make sure it doesn't root from any dropped bits,  Creeping Jenny the other name for the golden leafed one often recommeded for near ponds and bog gardens - can be rather too invasive there if not watched carefully and removed as it spreads out of bounds.  Yellow flowers are pretty though, and it is virtually indestructable.

I hope that it is invasive, I acquired it to compete with my neighbours 3 Russian vines.