They are antirrhinums (snapdragons) which have overwintered. They have naturalized in many parts of the UK.
Paul B3 said:
Antirrhinum cultivar ; a weed to some or a valuable garden plant to others .
They are Snapdragons, Antirrhinum, they look like a dwarf variety. Kids love them, if you gently pinch the sides of the flower they open their mouths, release and they snap shut There's no 'should' about weeds, you only decide what you want to keep. My garden has loads of what others call weeds, and I dig out things other people choose to plant. Some lovely plants can make areal nuisance of themselves in some gardens and need to be cosseted in others just to keep them alive. All part of the fun of gardening!