It's supposed to be introduced to Britain and Ireland by the Romans. It's also called Goutweed, Pigweed and Bishop weed.
To a lot of gardeners It's considered a pernicious weed and it's underground rhizome like roots. Some people spray it with an herbicide but I just pull it out with a fork because I don't believe in weedkillers. It's not really a pernicious weed It's a garden escapee.
Apparently a lot of Victorian gardeners use to deliberately plant Ground Elder and used it to treat Gout and eat it in salads and soups and stews. It's also an antinflammary. It's often sold in market stall in Krakow and the Ukraine. I have been to Krakow but I never saw any Ground Elder for sale.
Wouldn't it be ironic to think that the pernicious weed you have in your Victorian garden was deliberately planted in amongst the herbaceous perennials and shrubs?