It looks like Geranium macrorrhizum, either Ingwersens or Bevans Variety, depending on flower colour, that's run out of root room. Looks like it wants turning out, breaking into smaller sections, then two or three sections replanting into new compost. Its not a weed and is often planted in shadier areas of gardens, where it can cover quite a large area over time.

I agree with the id.
but when it has become too big I pull it out as it is then a weed in my opinion.
as a traditional weed it isn't one.

Unless you mean the little shrubby plant at the right hand end which cold be a self seeded willow ?

Many thanks for your comments, I think that Gerenaium is the most likely it has been in this trough for many years and was only moved when we had to change our oil tank.

It formed part of the base of the screen !!

Thank you again.

C J Craig, Limavady N. Ireland