Whilst I agree with all of the above, surely even at that angle the yellow hairs on the face will be visible?
I'm leaning towards one of the cuckoos perhaps, particularly with the sparseness of the hairs on the abdomen.
Imaginos,
Looking again at the picture there are some light coloured hairs on the edge of the face visible but what colour they are, is debatable, the angle of the head is from the side and rear so that the facial hairs may just be hidden.
I see your point about considering it to be one of the Bombus (Psithyrus) species but only one of these has a red tail and that is B.(P) rupestris. That species has, these days, a very restricted range mostly along the South Coast, although I believe it is expanding its range again.
Old bees, and this appears to be one, do lose their hair over time exposing areas of cuticle where they have been rubbed away. Looking at the hind leg there does appear to be a hint of a corbicular, which would work against it being a Cuckoo Bee.
Having lost my copy of Photoshop 7 in a recent Netski virus attack, I cannot do the enlarging, cropping and enhancement I would like, using the Microsoft picture editor, which is a rubbish programme in comparrison.
Unless other pictures are available of this bee taken from other angles, I'm afraid we will just have to differ in our opinions as to its identity.
Harry.