That looks like a shrub called Leycesteria, Daffadowndi.

Louise is correct Daffa. The common name is Pheasant Berry. The birds love those seeds you can see forming in the middle of the spent flowers. It will self seed but the seedlings are easy to pull out.

Thank you both , the stems are so huge I was fearfull that it was japaneze knotwood or something else gruesome.