Type of Viper's Bugloss?

[Anny]

Can anyone help me identify this strange plant?
It arrived with some soil dumped with discarded stone onto a neglected building site which was an old chapel, next door (in Bath, UK).
It started flowering at the end of April and is still going strong in July.
I looked at the area nearby where the soil came from but there are no similar plants, so the seeds must have been dormant.
Someone suggested it could be Viper's Bugloss, but the leaves are different and the flower heads are curled up and not in spaced-out spires.
It is so beautiful that I shall definitely save the seeds.

Anny

[Dorts]

Hi Anny. Welcome to WAB.
It's Tansy-leaved Phacelia - Phacelia tanacetifolia. Sometimes just refered to as Phacelia.
The bees love it.
Dorts.

[leifus]

seconded, it's a lovely plant, despite not being native, and can grow in vast quantities