It seems to be a Tree Bumblebee (Bombus hypnorum):
BWARS celebrates 2011 as the 10th year since the first record of this species in Britain. More info on their info sheet (pdf):
Hi Florin, yes the pictures and description of the Tree Bumble bee definitely matches the ones we've got.
For info, we are in Manchester.
We can see male bees 'dancing' around the entrance to their nest during the day - trying to attract a female.
Thanks for your help.
Hi, we have got these in our garden in Reading this year but no dancing:) the Bumblebee Conservation Trust are tracking the spread of this bee and their behaviour, I put the link below, there's a video of a nest site too: