Not a bee but a super fly. It is the common Bee-fly, Bombylius major - 'common' because there are other less common species in the UK. This is a classic springtime fly which is often seen hovering and darting about on warm spring days (where have they gone this weekend?). The long proboscis is used for feeding from springtime flowers whose nectar is produced at the base of long tubed flowers such as primroses. They have a very interesting life history - females scatter their eggs close to the nesting tunnels of solitary bees, the emerging bee-fly larvae then crawl into these tunnels to feed on the store of pollen and nectar put their for the bees own larvae. Adult flies emerge in the spring and the whole process starts again.
They have always been there to see in the countryside but do appear to have become more common in gardens over the last 10-15 years, somewhat as a success of their hosts I suspect.
It was enjoying the hyacinths in the lovely sunshine we've got in Bristol today. They're such interesting little creatures, so worth putting so much effort into the garden when we get rewarded with lots of lovely insects.