Briar

A (Eurasian) tree sparrow, Passer montanus, in a wild rose bush, or briar.

The tree sparrow is sometimes called a mountain sparrow elsewhere in Europe.  Both sexes have similar plumage.

In the UK, its preferred habitat is generally open woodland with the urban niche occupied by its relative, the house sparrow.  You can easily tell them apart because the tree sparrow has white cheeks with a central black spot and a chestnut cap and nape.  Compare the house sparrows that I blipped on the 19th September:
https://www.blipfoto.com/entry/3287221748109414093