This ID could be one of two ,
Osmia leaiana or caerulescens by BWARS
Confidence: I’m as sure as I can be.
Notes: This is a male Osmia, and almost certainly one of these two species. Photo id is not really possible.
I have gone with Osmia leaiana as the Osmia caerulescens which frequent my garden are gold in colour, I realise that there is variation in colour but I see many gold Osmia c and only one or two of this bee. So this ID is not a certain one but you can see the difference by looking at my photo of a O caerulescens
One of two small Osmia bees frequently occurring in gardens as well as woodland clearings and edges. The males of both O. leaiana and O. caerulescens are extremely hard to distinguish, being about 6mm long, shining metallic green and having bright ginger hairs when fresh. The best character is microscopic: look at the downward-sloping front surface of the first gastral tergite. It is shining in O. caerulescens and matt with reticulation in O.
Restricted to England and Wales. It is less frequently found than O. caerulescens, but occurs in similar habitats. Overseas: Europe, although at higher altitudes in southern areas; also north-west Africa, also at higher altitudes.
The species may be encountered almost anywhere in England and Wales, but it requires cavities in dead wood, walls or cliffs for nesting….BWARS