Anyone Know What This Is? (flower)

[mudsticks]

I tried that with Google images and it went just as well as your app

I don't understand what happened here.

But are we any closer to a positive id.??

My money's back on a form of fumitory.

 

[Alex H]

Any leaves??

Was it multi stemmed, or single stalked ??

Single stalk, leaves are the light green ones you can see in the original photo.

 

[mudsticks]

If it's the segmented leaves.

Then I'd be pretty sure is a variety of fumitory as detailed above.

The disturbance of the building work will have brought its dormant seeds close enough to the soil surface to germinate.

Its not a troublesome weed.