I think it's a briar rose but can't see it too clearly.

It could be the rootstock sprouting from an old rose bush.

Yes, good old fashioned wild rose.

I think this is specifically Rosa arvensis (Field Rose). It's a lax, scandent plant that is quite common and much less upright and sturdy than the other native species Rosa canina (Dog Rose). It's flowers can vary from white to pink but mostly white and smaller than the other species. It was used as a root stock once.