I ran the picture through an AI plant identifying app, which said that it is Japanese knotweed.
Looks like it to me. Corner of Devonshire wall has been destroyed by that twice in the past.
We sometimes get it growing in front garden and I just pull it out by the root before it can get established. Nightmare weed.
Just pulling it up won’t get rid of it. It is a rhizome and the tiniest section remaining can spread. It’s illegal to put it in the Lewisham brown bins. A neighbour had some about 20 years ago, which ironically had been introduced to her garden by Lewisham Council road repairers. She injected the stems with strong poison regularly until the plants and their rhizomes eventually died. They have never recurred and thank goodness, it never spread to us!
Lewisham’s website states:
Here is some guidance on how to identify it:
There is guidance here on how to dispose of it legally: