Can anyone identify this please?

[psychedelephant]

Gorgeous frothy white blossom that usually blooms slightly later in spring, no idea what it is.
You may be able to see rose leaves in that photo but the leaf that belongs to this plant can be seen in the lower part of the photo growing down the fence.

Its some sort of clematis maybe Montana?

Nope I don't think so, it's bushy and double-flowered. The leaf is different too.

Magnolia Stellata would be my guess.

Wrong leaves, wrong petal shape for Magnolia stellata. The stems shooting skyward are very rose-like - is that a possibility?

I think it's a Philadelphus - I'll get some pix - there are various ones

I thought Philadelphus too.

Philadelphus 'Belle Etoile' from three distances - what do you think OP?

Thanks for replies and photos!
florentina I don't think it's a magnolia, the flowers are bushier than magnolia.
Mere those are rose leaves from an intertwined rose, the leaves that belong to this plant are the ones toward the bottom of the pic. (That rose would grow right over the house if we let it.)
onalong Nan Philadelphus looks similar, esp the very frothy varieties like 'Manteau d'Hermine' and Virginal, but ours has no scent - ? The flowers are clumpy and bushy, not long, evenly spaced arms of flowers as in your photos.
Just going to charge my phone and get a closer photo of flowers and leaves.

Yes close ups please! No fragrance means it can't be a Philadelphus though. Also - whereabouts are you? Phila not in flower yet here (I have one - it's only just budding with leaves). I'm south-west England.

I'd say clematis.

Too early for philadelphus.

Any better? Apologies for broken trellis
I've tried PlantSnap, which tells me it's either a rose or a legume (doubtful). I'm not an experienced gardener but dh and his family are and no one seems to know what it is.
If it helps I think this year it's flowering quite early (I expected flowers in May). It's in a fairly sheltered area on that fence between two terraced houses (and there's a tall brick wall and school building beyond), south-facing garden. There's a lot more glass right there than there used to be (neighbours added a kitchen extension and we got bi-fold doors) so I wonder if that's anything to do with it.
We're in London.

Again any visble rose thorns/leaves are from the rose, not the mystery plant

Is it Exochorda, The Bride. Mine is in bud at the moment.

exochorda 'the bride'

Cross post!

Ooh yes, I think that's it! Thanks very much!

It's gorgeous! I want one now... beetles off to do internet garden shopping...

onalong I don't blame you, afaik its very low-maintenance and every year without fail there's this amazing display. The previous owner loved gardening but I doubt the current neighbour does anything at all to it. I wondered what it was called partly so I could figure out where else I could plant one.