This is a Bellis perennis which forms part of the spring bedding scheme on the Victorian terrace.
BUT ... it has this strange mutation known as FASCIATION.
When plants have fasciation the stems and flowerheads appear flattened and elongated. This can be caused by genetic mutation, viral infection or as a reaction to damage from frost, animals or machinery.
It's quite harmless - in fact plant breeders will often use it to their advantage to produce new plants. I think it's quite exciting to see what nature thows up!...