This is the female of the Hairy-footed Flower bee, Anthophora plumipes, and one of the UK's 260 or so species of solitary bees. The males look quite different being gingery in colour with yellow faces, but both have a fast darting flight and attend to flowers very quickly often hovering near them. They often nest gregariously in holes in lose mortar of brick walls or sometimes in lose spoil/soil heaps. The female provisions her nest burrow with a mixture of pollen and nectar. They are very much a springtime bee and can be seen from late March, but all done by June.
Has to be said they are entirely harmless and 'squishing' is generally not required and certainly not recommended